diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 2fbfc9f584e..f8a55cc49d5 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -2387,18 +2387,6 @@
      {}
     ]
    ],
-   "css/iframe/mozbrowser_navigation.html": [
-    [
-     "/_mozilla/css/iframe/mozbrowser_navigation.html",
-     [
-      [
-       "/_mozilla/css/iframe/mozbrowser_navigation_ref.html",
-       "=="
-      ]
-     ],
-     {}
-    ]
-   ],
    "css/iframe/multiple_external.html": [
     [
      "/_mozilla/css/iframe/multiple_external.html",
@@ -8947,11 +8935,6 @@
      {}
     ]
    ],
-   "css/iframe/mozbrowser_navigation_ref.html": [
-    [
-     {}
-    ]
-   ],
    "css/iframe/multiple_external_child.html": [
     [
      {}
@@ -11102,101 +11085,6 @@
      {}
     ]
    ],
-   "mozilla/mozbrowser/helper.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_contentDocument_inner.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_privateContent_grandchild.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_privateContent_inner.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe1.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe2.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe3.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_iframe_child.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_iframe_grandchild.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_iframe_harness.js": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsericonchange_event_test.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowserlocationchange_event_iframe.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_iframe.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_nested_iframe.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_no_params_alert.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event_iframe.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/redirect_final.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/redirect_init.html": [
-    [
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/stash.py": [
-    [
-     {}
-    ]
-   ],
    "mozilla/nested_asap_script.js": [
     [
      {}
@@ -33471,96 +33359,6 @@
      {}
     ]
    ],
-   "mozilla/mozbrowser/crossorigin_xhr.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/crossorigin_xhr.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_goback.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/iframe_goback.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_reload_twice.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/iframe_reload_twice.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/iframe_visibility.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/iframe_visibility.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_iframe_parentage.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowser_iframe_parentage.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowser_loadevents.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowser_loadevents.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsericonchange_event.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowsericonchange_event.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowserlocationchange_event.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowserlocationchange_event.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsersecuritychange_event.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowsersecuritychange_event.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/private_browsing.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/private_browsing.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/redirect.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/redirect.html",
-     {}
-    ]
-   ],
-   "mozilla/mozbrowser/reload.html": [
-    [
-     "/_mozilla/mozilla/mozbrowser/reload.html",
-     {}
-    ]
-   ],
    "mozilla/mql_borrow.html": [
     [
      "/_mozilla/mozilla/mql_borrow.html",
@@ -62602,14 +62400,6 @@
    "e30451b16fc0c4b025a2160e6c7b849901150718",
    "support"
   ],
-  "css/iframe/mozbrowser_navigation.html": [
-   "7a17922ce48c8138284ad1a1f0f88317df35b541",
-   "reftest"
-  ],
-  "css/iframe/mozbrowser_navigation_ref.html": [
-   "368a46cfb7c6cdce26381121d803427d6ad93c69",
-   "support"
-  ],
   "css/iframe/multiple_external.html": [
    "79df63cbb113c57ccacf5734a6d14e29d73478a5",
    "reftest"
@@ -66562,142 +66352,6 @@
    "1311e72e0a0dafa6fae594ca1ce2deca164acd36",
    "testharness"
   ],
-  "mozilla/mozbrowser/crossorigin_xhr.html": [
-   "e716ee75552f0e531fef1a71b20799ccb8b221d9",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/helper.html": [
-   "652e88e7a84b50ca1d4ed3cc2d1f1e354fb9ab32",
-   "support"
-  ],
-  "mozilla/mozbrowser/iframe_contentDocument_inner.html": [
-   "a098b74e081838bcbf4ceb854a48a57eb5ae3cab",
-   "support"
-  ],
-  "mozilla/mozbrowser/iframe_goback.html": [
-   "a850e2549dfdbcfbb344ccc23ff03717d392bfdc",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/iframe_privateContent_grandchild.html": [
-   "13d4e88f2581ff7d5cbbf149463563d0754978fe",
-   "support"
-  ],
-  "mozilla/mozbrowser/iframe_privateContent_inner.html": [
-   "354b3b6d6596559bac45119db6549f1347b93bef",
-   "support"
-  ],
-  "mozilla/mozbrowser/iframe_reload_twice.html": [
-   "c6e6cc7ca336154723c658fb8cae8989ca8b7ee7",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/iframe_visibility.html": [
-   "c2a2df3f85f7ed1d76fbc694fe247071050ebb81",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html": [
-   "30fa150f6f22a989bf7e85d3b367ec7d61f57f09",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe1.html": [
-   "375566a899295a1da1685cd85127c2da60e1eee8",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe2.html": [
-   "e4d4a2acd91a4f12323b5aca458a5c4068e70782",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe3.html": [
-   "9d714203485baed8faff37c312190dd384769c83",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_iframe_child.html": [
-   "a51e76f9c72896a539b08d40f48fef0412336a34",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_iframe_grandchild.html": [
-   "441c2e80ad3ecc9da321507a3c41b3c346bea0f0",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_iframe_harness.js": [
-   "c5db7a8f3c32f79a4e24d176cb95563a999240e5",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowser_iframe_parentage.html": [
-   "3f03a10f8f8c72cbd0a73fc130f705246c308871",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowser_loadevents.html": [
-   "03ef403ece408147f23f5dc898a0509102c4d75c",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowsericonchange_event.html": [
-   "fbaeb75787aa039e506c32ec0487dc05dc6280cf",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowsericonchange_event_test.html": [
-   "61e39bc9ead6d4bfc9bf60bed3323753dc0e791a",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowserlocationchange_event.html": [
-   "35a0671b553ae5787b8444deac127e2ee071d0f7",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowserlocationchange_event_iframe.html": [
-   "ed175a1b2426de141ccb47e4d13c88ff0db0506e",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowsersecuritychange_event.html": [
-   "58a58e552f21dd650020197b7e28c87c4d84e691",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html": [
-   "ff8971b64dda52903009697dc56df6b3a9cecdb3",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_iframe.html": [
-   "1cd97f725237d9ccba830a2e7f61b85da82319c5",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_nested_iframe.html": [
-   "4b40aeb217cfe9d557dbd4b87120b788ba7a0fd8",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowsershowmodalprompt_event_no_params_alert.html": [
-   "8c67b9c24de045fe36be9ff74a0700d7e7af6588",
-   "support"
-  ],
-  "mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html": [
-   "2beae7d4e20e0b535144ac91113a73724f970321",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event_iframe.html": [
-   "d7a0b1eced93ae16b2ccc7d1d1f2b1d383ff75ed",
-   "support"
-  ],
-  "mozilla/mozbrowser/private_browsing.html": [
-   "bc8f9bfde5b6eb53ec1362b0cfae5d300af15c7e",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/redirect.html": [
-   "7377e38b6bdaea746d8e3c2801112200dca502d2",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/redirect_final.html": [
-   "db82c9a14bc76e3548200bc2e507d6044660514c",
-   "support"
-  ],
-  "mozilla/mozbrowser/redirect_init.html": [
-   "ab668d7af80b7560bf3afa732b1198e2825929e9",
-   "support"
-  ],
-  "mozilla/mozbrowser/reload.html": [
-   "f8c4f6b0ccf95426a3e6816fce5490ef9704e267",
-   "testharness"
-  ],
-  "mozilla/mozbrowser/stash.py": [
-   "5513229f79ab37de67eb4d60ea9dd23cd31d133f",
-   "support"
-  ],
   "mozilla/mql_borrow.html": [
    "f8f9adebe09f9473a52e5ec4f075540b10b32d7e",
    "testharness"
diff --git a/tests/wpt/mozilla/meta/css/iframe/mozbrowser_navigation.html.ini b/tests/wpt/mozilla/meta/css/iframe/mozbrowser_navigation.html.ini
deleted file mode 100644
index 7ed29aa037c..00000000000
--- a/tests/wpt/mozilla/meta/css/iframe/mozbrowser_navigation.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mozbrowser_navigation.html]
-  type: reftest
-  prefs: [dom.mozbrowser.enabled:true]
-  disabled: https://github.com/servo/servo/issues/10924
diff --git a/tests/wpt/mozilla/meta/mozilla/mozbrowser/__dir__.ini b/tests/wpt/mozilla/meta/mozilla/mozbrowser/__dir__.ini
deleted file mode 100644
index 6a4996ca794..00000000000
--- a/tests/wpt/mozilla/meta/mozilla/mozbrowser/__dir__.ini
+++ /dev/null
@@ -1 +0,0 @@
-prefs: ["dom.mozbrowser.enabled:true"]
diff --git a/tests/wpt/mozilla/meta/mozilla/mozbrowser/iframe_visibility.html.ini b/tests/wpt/mozilla/meta/mozilla/mozbrowser/iframe_visibility.html.ini
deleted file mode 100644
index 6b5a309d200..00000000000
--- a/tests/wpt/mozilla/meta/mozilla/mozbrowser/iframe_visibility.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[iframe_visibility.html]
-  type: testharness
-  disabled: https://github.com/servo/servo/issues/11825
diff --git a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowser_loadevents.html.ini b/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowser_loadevents.html.ini
deleted file mode 100644
index 2d0ba01c141..00000000000
--- a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowser_loadevents.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[mozbrowser_loadevents.html]
-  type: testharness
-  [mozbrowserloadstart, mozbrowserconnected and mozbrowserloadend are dispatched]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowserlocationchange_event.html.ini b/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowserlocationchange_event.html.ini
deleted file mode 100644
index 3535c215cdc..00000000000
--- a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowserlocationchange_event.html.ini
+++ /dev/null
@@ -1,6 +0,0 @@
-[mozbrowserlocationchange_event.html]
-  type: testharness
-  expected: TIMEOUT
-  [Browser API; mozbrowserlocationchange event]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowsersecuritychange_event.html.ini b/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowsersecuritychange_event.html.ini
deleted file mode 100644
index 509699c9ca4..00000000000
--- a/tests/wpt/mozilla/meta/mozilla/mozbrowser/mozbrowsersecuritychange_event.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[mozbrowsersecuritychange_event.html]
-  type: testharness
-  [mozbrowsersecuritychange event is dispatched when content security state changes]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation.html b/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation.html
deleted file mode 100644
index ea8ae85531d..00000000000
--- a/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation.html
+++ /dev/null
@@ -1,33 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-<meta charset="utf-8">
-<style>
-iframe {
-    display: block;
-    border: 1px solid black;
-    width: 500px;
-    height: 300px;
-    margin-left: 10px;
-    margin-top: 0px;
-}
-</style>
-<link rel="match" href="mozbrowser_navigation_ref.html">
-</head>
-<body>
-<iframe mozbrowser="true" src="data:text/html,Hello%20world"></iframe>
-<script>
-var iframe = document.getElementsByTagName('iframe')[0];
-iframe.addEventListener('load', function first() {
-    iframe.removeEventListener('load', first);
-    iframe.src = "data:text/html,Foo";
-    iframe.addEventListener('load', function() {
-        iframe.goBack();
-        iframe.offsetHeight;    // flush layout
-        document.documentElement.classList.remove("reftest-wait");
-    }, false);
-}, false);
-</script>
-</body>
-</html>
-
diff --git a/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation_ref.html b/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation_ref.html
deleted file mode 100644
index 10e6dac4888..00000000000
--- a/tests/wpt/mozilla/tests/css/iframe/mozbrowser_navigation_ref.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!DOCTYPE html>
-<html>
-<meta charset="utf-8">
-<style>
-iframe {
-    display: block;
-    border: 1px solid black;
-    width: 500px;
-    height: 300px;
-    margin-left: 10px;
-    margin-top: 0px;
-}
-</style>
-<body>
-<iframe src="data:text/html,Hello%20world"></iframe>
-</body>
-</html>
-
-
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/crossorigin_xhr.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/crossorigin_xhr.html
deleted file mode 100644
index 180f3a915b6..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/crossorigin_xhr.html
+++ /dev/null
@@ -1,22 +0,0 @@
-<head>
-<title>cross origin xhr() with mozbrowser</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-  var xhr = new XMLHttpRequest();
-  xhr.open("GET", "http://www2.web-platform.test:8000");
-  xhr.send();
-
-  xhr.onerror = this.unreached_func("Cross origin xhr() should not have failed");
-
-  xhr.onload = this.step_func_done(() => {
-    assert_equals(xhr.status, 200, "Cross origin xhr() is successful");
-  });
-});
-
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/helper.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/helper.html
deleted file mode 100644
index dee1ea597e5..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/helper.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<!doctype html>
-<html>
-<body>
-    <p>test</p>
-</body>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_contentDocument_inner.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_contentDocument_inner.html
deleted file mode 100644
index 8336b0744a8..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_contentDocument_inner.html
+++ /dev/null
@@ -1,3 +0,0 @@
-<html><body><div id="test">Normal iFrame</div></body>
-<script>alert(document.cookie)</script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_goback.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_goback.html
deleted file mode 100644
index 353051043e1..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_goback.html
+++ /dev/null
@@ -1,37 +0,0 @@
-<head>
-<title>iframe.goBack()</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-
-  var url2 = "data:,a";
-  var url1 = `data:text/html,<script>setTimeout(() => location.assign("${url2}"), 0)</${"script"}>`;
-
-  var locations = []
-  var expected_locations = ["about:blank", url1, url2, url1];
-
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-  iframe.src = url1;
-
-  iframe.addEventListener("mozbrowserlocationchange", t.step_func(e => {
-    locations.push(e.detail.url);
-    if (e.detail.url == url2) {
-      iframe.goBack();
-    }
-    if (locations.length == expected_locations.length) {
-       assert_array_equals(locations, expected_locations);
-       t.done();
-    }
-  }));
-
-  document.body.appendChild(iframe);
-
-});
-
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_grandchild.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_grandchild.html
deleted file mode 100644
index 5af0ff72802..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_grandchild.html
+++ /dev/null
@@ -1,4 +0,0 @@
-<span id="cookie"></span>
-<script>
-document.querySelector('#cookie').innerHTML = document.cookie;
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_inner.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_inner.html
deleted file mode 100644
index 30d5bc8598a..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_privateContent_inner.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<html>
-<body>
-<div id="test">Private iFrame</div>
-</body>
-<script>document.cookie = "private=active;path=/";</script>
-<iframe src="iframe_privateContent_grandchild.html"></iframe>
-<script>
-var iframe = document.querySelector('iframe');
-iframe.onload = function() {
-  alert(document.cookie + ' ' + iframe.contentDocument.querySelector('#cookie').textContent);
-};
-</script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_reload_twice.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_reload_twice.html
deleted file mode 100644
index 0b42fafbc55..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_reload_twice.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title>Reloading an iframe twice doesn't panic</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<iframe></iframe>
-<script>
-async_test(function(t) {
-  var iframe = document.querySelector('iframe');
-  var loaded = false;
-  iframe.onload = t.step_func(function() {
-    if (!loaded) {
-      loaded = true;
-      iframe.reload();
-      iframe.reload();
-    } else {
-      t.done();
-    }
-  });
-  iframe.mozbrowser = true;
-  iframe.src = "about:blank";
-});
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_visibility.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_visibility.html
deleted file mode 100644
index 8987998993c..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_visibility.html
+++ /dev/null
@@ -1,115 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<head>
-<title>Iframe visibility tests</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-    <script>
-    async_test(function(t) {
-        var expectedVisibilities = [false, true];
-        var receivedVisibilities = [];
-
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = true;
-        iframe.src = "helper.html";
-
-        //Alternate the iframe's visibility and fire mozbrowservisibilitychange
-        iframe.onload = t.step_func(function() {
-            iframe.setVisible(false);
-            iframe.setVisible(true);
-       });
-
-        iframe.addEventListener("mozbrowservisibilitychange", t.step_func(e => {
-            assert_equals(iframe.getVisible(), e.detail.visible);
-            receivedVisibilities.push(e.detail.visible);
-            if (receivedVisibilities.length == expectedVisibilities.length) {
-                assert_array_equals(receivedVisibilities, expectedVisibilities);
-                t.done();
-            }
-        }));
-
-        document.body.appendChild(iframe);
-    }, "Iframe visibility setter/getter");
-
-    async_test(function(t) {
-      var iframe = document.createElement("iframe");
-      iframe.mozbrowser = true;
-      iframe.src = "helper.html";
-      var start = null;
-      document.body.appendChild(iframe);
-      iframe.onload = t.step_func(function() {
-        var element = iframe.contentWindow.document.querySelector("p");
-        var animationCompletesAfterResumingVisibility = false;
-        var nonVisibleAnimationStopped = false;
-        element.style.position = 'relative';
-        element.style.right = "0px";
-        var step = t.step_func(function(timestamp) {
-          if (!start) start = timestamp;
-          var progress = timestamp - start;
-          element.style.right = Math.min(progress/5, 100) + "px";
-          if (progress < 500) {
-            iframe.contentWindow.requestAnimationFrame(step);
-          }
-        });
-
-        iframe.setVisible(false);
-
-        iframe.contentWindow.setTimeout(t.step_func(function(){
-            nonVisibleAnimationStopped = element.style.right === '0px';
-            iframe.setVisible(true);
-        }),1000);
-
-        iframe.contentWindow.setTimeout(t.step_func(function(){
-            animationCompletesAfterResumingVisibility = element.style.right === '100px';
-            assert_true(nonVisibleAnimationStopped);
-            assert_true(animationCompletesAfterResumingVisibility);
-            t.done();
-        }),2000);
-
-        iframe.contentWindow.requestAnimationFrame(step);
-      });
-    }, 'Requesting animation frame composites only when frame is visible');
-
-    async_test(function(t) {
-      var iframe = document.createElement("iframe");
-      iframe.src = "http://web-platform.test:8000/common/blank.html";
-      iframe.mozbrowser = true;
-      iframe.onload = t.step_func(function() {
-          iframe.addEventListener("mozbrowservisibilitychange", t.step_func(function() {
-              var startTime = Date.now();
-              iframe.contentWindow.setTimeout(t.step_func(function() {
-                  assert_true(Date.now() - startTime >= 1000);
-                  t.done();
-              }), 1);
-          }));
-        iframe.setVisible(false);
-      });
-      document.body.appendChild(iframe);
-    }, 'Minimum setTimeout of 1s when pipeline is invisible');
-
-    async_test(function(t) {
-      var iframe = document.createElement("iframe");
-      var destination = "helper.html";
-      iframe.src = "http://web-platform.test:8000/common/blank.html";
-      iframe.mozbrowser = true;
-      iframe.onload = t.step_func(function() {
-          iframe.addEventListener("mozbrowservisibilitychange", t.step_func(function() {
-              iframe.src = destination;
-          }));
-          if (iframe.src !== destination) {
-              iframe.setVisible(false);
-          } else {
-              var startTime = Date.now();
-              iframe.contentWindow.setTimeout(t.step_func(function() {
-                  assert_true(Date.now() - startTime >= 1000);
-                  t.done();
-              }), 1);
-          }
-      });
-      document.body.appendChild(iframe);
-    }, 'Minimum setTimeout of 1s persists after new page is loaded');
-
-    </script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html
deleted file mode 100644
index 60f4686c5a9..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow.html
+++ /dev/null
@@ -1,27 +0,0 @@
-<head>
-<title>Browser API; mozbrowseropenwindow event</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-  iframe.src = "mozbrowser_click_fires_openwindow_iframe1.html";
-
-  iframe.addEventListener("mozbrowseropenwindow", t.step_func(function(e) {
-    var expectedURL = new URL("mozbrowser_click_fires_openwindow_iframe3.html", window.location.href);
-    assert_equals(e.detail.target, "_blank");
-    assert_equals(e.detail.url.toString(), expectedURL.toString());
-    t.done();
-  }));
-
-  document.body.appendChild(iframe);
-
-});
-
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe1.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe1.html
deleted file mode 100644
index ed6fbe47a42..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe1.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<html>
-  <body>
-    Frame 1: <a id="anchor" href="mozbrowser_click_fires_openwindow_iframe2.html">go</a>.
-  </body>
-  <script>
-    document.getElementById("anchor").click()
-  </script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe2.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe2.html
deleted file mode 100644
index 9f54b30db7c..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe2.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<html>
-  <body>
-    Frame 2: <a id="anchor" href="mozbrowser_click_fires_openwindow_iframe3.html" target="_blank">go</a>.
-  </body>
-  <script>
-    document.getElementById("anchor").click()
-  </script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe3.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe3.html
deleted file mode 100644
index 9085a9f7348..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_click_fires_openwindow_iframe3.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<html>
-  <body>
-    Frame 3.
-  </body>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_child.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_child.html
deleted file mode 100644
index 92c1da900fd..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_child.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<script src="mozbrowser_iframe_harness.js"></script>
-<body>
-  <iframe src="mozbrowser_iframe_grandchild.html"></iframe>
-</body>
-<script>
-    send_test_results({
-        "id": 'aaee4290-6a78-4932-a1d1-fbbe158fb473',
-        "parent": window.parent === window,
-        "top": window.top === window,
-    });
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_grandchild.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_grandchild.html
deleted file mode 100644
index cca52b544ec..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_grandchild.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<script src="mozbrowser_iframe_harness.js"></script>
-<body>
-</body>
-<script>
-    send_test_results({
-        "id": 'a94c0025-08dc-49a6-8f98-fbbaacfdd296',
-        "parent": window.parent !== window,
-        "grandparent": window.parent.parent === window.parent,
-        "top": window.top === window.parent,
-    });
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_harness.js b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_harness.js
deleted file mode 100644
index f4ef511d1de..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_harness.js
+++ /dev/null
@@ -1,26 +0,0 @@
-function get_test_results(id) {
-    async_test(function(test) {
-        var timer = window.setInterval(test.step_func(loop), 100);
-        function loop() {
-            var xhr = new XMLHttpRequest();
-            xhr.open('GET', 'stash.py?id=' + id);
-            xhr.onreadystatechange = test.step_func(function() {
-                assert_equals(xhr.status, 200);
-                if (xhr.responseText) {
-                    assert_equals(xhr.responseText, "OK");
-                    test.done();
-                    window.clearTimeout(timer);
-                }
-            });
-            xhr.send();
-        }
-    });
-}
-
-function send_test_results(results) {
-    var ok = true;
-    for (result in results) { ok = ok && results[result]; }
-    var xhr = new XMLHttpRequest();
-    xhr.open('POST', 'stash.py?id=' + results.id);
-    xhr.send(ok ? "OK" : "FAIL: " + JSON.stringify(results));
-}
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_parentage.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_parentage.html
deleted file mode 100644
index 45610858ae0..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_iframe_parentage.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title>Check the frame heriarchy</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="mozbrowser_iframe_harness.js"></script>
-<body>
-</body>
-<script>
-    var iframe = document.createElement("iframe");
-    iframe.mozbrowser = "true";
-    iframe.src = "mozbrowser_iframe_child.html";
-    document.body.appendChild(iframe);
-
-    get_test_results('cdea5bf0-667e-407c-878c-6b5cfa623fd6');
-    get_test_results('aaee4290-6a78-4932-a1d1-fbbe158fb473');
-    get_test_results('a94c0025-08dc-49a6-8f98-fbbaacfdd296');
-    send_test_results({
-        "id": 'cdea5bf0-667e-407c-878c-6b5cfa623fd6',
-        "parent": window.parent === window,
-        "top": window.top === window,
-    });
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_loadevents.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_loadevents.html
deleted file mode 100644
index 8992e7e743a..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowser_loadevents.html
+++ /dev/null
@@ -1,47 +0,0 @@
-<head>
-  <title>mozbrowserloadstart, mozbrowserconnected and mozbrowserloadend are dispatched</title>
-  <script src="/resources/testharness.js"></script>
-  <script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-  <script>
-
-    async_test(function(t) {
-
-      var has_reloaded = false;
-      var expectedEvents = [
-        "mozbrowserloadstart",
-        "mozbrowserconnected",
-        "mozbrowserloadend",
-        "mozbrowserloadstart",
-        "mozbrowserconnected",
-        "mozbrowserloadend",
-      ];
-
-      var receivedEvents = [];
-
-      var iframe = document.createElement("iframe");
-      iframe.mozbrowser = "true";
-      iframe.src = "http://web-platform.test:8000";
-
-      for (var event_name of ["mozbrowserloadstart",
-                              "mozbrowserconnected",
-                              "mozbrowserloadend"]) {
-        iframe.addEventListener(event_name, t.step_func(e => {
-          receivedEvents.push(e.type);
-          if (receivedEvents.length == expectedEvents.length) {
-            assert_array_equals(receivedEvents, expectedEvents);
-            t.done();
-          } else {
-            if (e.type == "mozbrowserloadend") {
-              iframe.reload();
-            }
-          }
-        }));
-      }
-
-      document.body.appendChild(iframe);
-    });
-
-  </script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event.html
deleted file mode 100644
index eea0b431928..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event.html
+++ /dev/null
@@ -1,51 +0,0 @@
-<head>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-
-  var expectedEvents = [
-    {rel: "icon", href: "http://web-platform.test:8000/test1.ico", sizes: "any"},
-    {rel: "icon", href: "http://web-platform.test:8000/_mozilla/mozilla/mozbrowser/test2.ico", sizes: "16x16 24x24"},
-    {rel: "shortcut icon", href: "http://example.com/test3.ico", sizes: ""},
-    {rel: "apple-touch-icon", href: "http://web-platform.test:8000/test4.ico", sizes: ""},
-    {rel: "icon", href: "http://web-platform.test:8000/test5.ico", sizes: ""},
-    {rel: "icon", href: "http://web-platform.test:8000/test6.ico", sizes: "any"},
-    {rel: "icon", href: "http://web-platform.test:8000/test6.ico", sizes: "32x32"},
-  ];
-
-  var receivedEvents = [];
-
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-  iframe.src = "mozbrowsericonchange_event_test.html";
-
-  iframe.addEventListener("mozbrowsericonchange", t.step_func(e => {
-
-    receivedEvents.push({
-      rel: e.detail.rel,
-      href: e.detail.href,
-      sizes: e.detail.sizes,
-    });
-
-    if (receivedEvents.length == expectedEvents.length) {
-      for (var i = 0; i < expectedEvents.length; i++) {
-        var e1 = expectedEvents[i];
-        var e2 = receivedEvents[i];
-        assert_equals(e1.rel, e2.rel);
-        assert_equals(e1.href, e2.href);
-        assert_equals(e1.sizes, e2.sizes);
-      }
-      t.done();
-    }
-  }));
-
-
-  document.body.appendChild(iframe);
-});
-
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event_test.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event_test.html
deleted file mode 100644
index 6693605e1e8..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsericonchange_event_test.html
+++ /dev/null
@@ -1,22 +0,0 @@
-<html>
-  <head>
-    <link rel="icon" href="/test1.ico" sizes="any">
-    <link rel="icon" href="./test2.ico" sizes="16x16 24x24">
-    <link rel="shortcut icon" href="http://example.com/test3.ico">
-    <link rel="not-icon" href="xxx">
-    <link rel="icon no-href">
-    <link rel="apple-touch-icon" href="/test4.ico">
-    <script>
-      setTimeout(function() {
-        var link = document.createElement("link");
-        link.rel = "icon";
-        link.href = "/test5.ico"
-        document.head.appendChild(link);
-        link = document.querySelector('link[href="/test1.ico"]');
-        link.href = "/test6.ico";
-        setTimeout(() => link.setAttribute("sizes", "32x32"), 0);
-      }, 0);
-    </script>
-  </head>
-  <body>123</body>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event.html
deleted file mode 100644
index 30abe74b92e..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event.html
+++ /dev/null
@@ -1,75 +0,0 @@
-<head>
-<title>Browser API; mozbrowserlocationchange event</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-
-  var url1 = "data:,1";
-  var url2 = "data:,2";
-  var url3 = "data:,3";
-
-  var received_events = []
-  var expected_events = [
-    "about:blank", false, false,
-    url1, true,  false,
-    url2, true,  false,
-    url3, true,  false,
-    url2, true,  true,
-    url1, true,  true,
-    "about:blank", false, true,
-    url1, true,  true,
-    url2, true,  true,
-    url3, true,  false,
-  ];
-
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-
-  var actions = [
-    function() {iframe.src = url1},
-    function() {iframe.src = url2},
-    function() {iframe.src = url3},
-    function() {iframe.goBack()},
-    function() {iframe.goBack()},
-    function() {iframe.goBack()},
-    function() {iframe.goForward()},
-    function() {iframe.goForward()},
-    function() {iframe.goForward()},
-  ];
-
-  var action_idx = 0;
-
-  iframe.addEventListener("mozbrowserlocationchange", t.step_func(e => {
-    received_events.push(e.detail.url);
-    received_events.push(e.detail.canGoBack);
-    received_events.push(e.detail.canGoForward);
-
-    if (action_idx < actions.length) {
-      actions[action_idx++]();
-    } else {
-       assert_array_equals(received_events, expected_events);
-       t.done();
-    }
-  }));
-
-  document.body.appendChild(iframe);
-
-});
-
-async_test(function(t) {
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-  iframe.src = "mozbrowserlocationchange_event_iframe.html";
-  iframe.addEventListener("mozbrowserlocationchange", t.step_func(function(e) {
-    var url = e.detail.url || e.detail.uri || e.detail;
-    var filename = url.split("/").pop();
-    if (filename === "yes.html") { t.done(); }
-  }));
-  document.body.appendChild(iframe);
-});
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event_iframe.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event_iframe.html
deleted file mode 100644
index 11c18e4cd45..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowserlocationchange_event_iframe.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<html>
-    <body></body>
-    <script>
-        window.location.assign("yes.html");
-    </script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsersecuritychange_event.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsersecuritychange_event.html
deleted file mode 100644
index 8cf0cc402f8..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsersecuritychange_event.html
+++ /dev/null
@@ -1,46 +0,0 @@
-<head>
-  <title>mozbrowsersecuritychange event is dispatched when content security state changes</title>
-  <script src="/resources/testharness.js"></script>
-  <script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-  <script>
-
-    async_test(function(t) {
-
-      const HTTP_URL = "http://web-platform.test:8000";
-      const HTTPS_URL = "https://web-platform.test:8443";
-
-      var urls = [ HTTP_URL, HTTPS_URL, HTTP_URL ];
-      var url_index = 0;
-
-      var expectedEvents = [
-        "insecure",
-        "secure",
-        "insecure",
-      ];
-
-      var receivedEvents = [];
-
-      var iframe = document.createElement("iframe");
-      iframe.mozbrowser = "true";
-      iframe.src = urls[url_index++];
-
-      iframe.addEventListener("mozbrowsersecuritychange", t.step_func(e => {
-
-        receivedEvents.push(e.detail.state);
-
-        if (receivedEvents.length == expectedEvents.length) {
-          assert_array_equals(receivedEvents, expectedEvents);
-          t.done();
-        } else {
-          iframe.src = urls[url_index++];
-        }
-      }));
-
-
-      document.body.appendChild(iframe);
-    });
-
-  </script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html
deleted file mode 100644
index ca63dad80cc..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event.html
+++ /dev/null
@@ -1,43 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title>Dispatch mozbrowsershowmodalprompt event for alert (issue #8352)</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<body></body>
-<script>
-    async_test(function(t) {
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = "true";
-        iframe.src = "mozbrowsershowmodalprompt_event_iframe.html";
-        iframe.addEventListener("mozbrowsershowmodalprompt", t.step_func(e => {
-            assert_equals(e.detail.promptType, "alert");
-            assert_equals(e.detail.message, "my alert message");
-            t.done();
-        }));
-        document.body.appendChild(iframe);
-    });
-
-    async_test(function(t) {
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = "true";
-        iframe.src = "mozbrowsershowmodalprompt_event_nested_iframe.html";
-        iframe.addEventListener("mozbrowsershowmodalprompt", t.step_func(e => {
-            assert_equals(e.detail.promptType, "alert");
-            assert_equals(e.detail.message, "my alert message");
-            t.done();
-        }));
-        document.body.appendChild(iframe);
-    }, "mozbrowsershowmodalprompt event from nested iframes triggering an alert");
-
-    async_test(function(t) {
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = "true";
-        iframe.src = "mozbrowsershowmodalprompt_event_no_params_alert.html";
-        iframe.addEventListener("mozbrowsershowmodalprompt", t.step_func(e => {
-            assert_equals(e.detail.promptType, "alert");
-            assert_equals(e.detail.message, "");
-            t.done();
-        }));
-        document.body.appendChild(iframe);
-    }, "Dispatch mozbrowsershowmodalprompt event for alert with no parameters");
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_iframe.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_iframe.html
deleted file mode 100644
index e9e8e84be54..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_iframe.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<html>
-    <body></body>
-    <script>
-    window.alert("my alert message");
-    </script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_nested_iframe.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_nested_iframe.html
deleted file mode 100644
index 9d9efd7f922..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_nested_iframe.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<html>
-    <body>
-        <iframe src="mozbrowsershowmodalprompt_event_iframe.html" />
-    </body>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_no_params_alert.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_no_params_alert.html
deleted file mode 100644
index f0a8adbd15e..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsershowmodalprompt_event_no_params_alert.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<html>
-    <body></body>
-    <script>
-    window.alert();
-    </script>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html
deleted file mode 100644
index 4809f302f2f..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title>Check if title_changed is too eager (issue #10782)</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<body></body>
-<script>
-    async_test(function(t) {
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = "true";
-        iframe.src = "mozbrowsertitlechangedeagerly_event_iframe.html";
-        iframe.addEventListener("mozbrowsertitlechange", t.step_func(e => {
-            assert_equals(e.type, "mozbrowsertitlechange");
-            assert_not_equals(e.detail, "Bar");
-        }));
-        iframe.addEventListener("load", t.step_func_done());
-        document.body.appendChild(iframe);
-    });
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event_iframe.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event_iframe.html
deleted file mode 100644
index b10a632092a..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/mozbrowsertitlechangedeagerly_event_iframe.html
+++ /dev/null
@@ -1,16 +0,0 @@
-<html>
-    <head>
-        <title>Foo</title>
-        <script>
-            var text =
-                    '<html xmlns="http://www.w3.org/1999/xhtml">' +
-                    '  <head>' +
-                    '    <title>Bar</title>' +
-                    '  </head>' +
-                    '</html>';
-            var parser = new DOMParser();
-            var doc = parser.parseFromString(text, "text/xml");
-        </script>
-    </head>
-    <body>Hello world</body>
-</html>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/private_browsing.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/private_browsing.html
deleted file mode 100644
index 7510998625f..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/private_browsing.html
+++ /dev/null
@@ -1,44 +0,0 @@
-<head>
-  <meta charset="utf8" />
-  <title>Private browsing</title>
-  <script src="/resources/testharness.js"></script>
-  <script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-  <script>
-    async_test(function(t) {
-      var privateFrame = document.createElement("iframe");
-      privateFrame.mozbrowser = true;
-      privateFrame.mozprivatebrowsing = true;
-
-      var gotGrandchildResult = false;
-      privateFrame.addEventListener("mozbrowsershowmodalprompt", t.step_func(e => {
-        assert_equals(e.detail.message, 'private=active private=active');
-        gotGrandchildResult = true;
-      }));
-
-      privateFrame.onload = t.step_func(function() {
-        assert_true(gotGrandchildResult);
-
-        var parent = privateFrame.parentNode;
-        parent.removeChild(privateFrame);
-
-        var iframe = document.createElement("iframe");
-        var promptDisplay = false;
-        iframe.mozbrowser = true;
-        iframe.onload = t.step_func(function() {
-          assert_true(promptDisplay);
-          t.done();
-        });
-        iframe.addEventListener("mozbrowsershowmodalprompt", t.step_func(e => {
-          promptDisplay = true;
-          assert_equals(e.detail.message, "");
-        }));
-        iframe.src = "iframe_contentDocument_inner.html";
-        parent.appendChild(iframe);
-      });
-      privateFrame.src = "iframe_privateContent_inner.html";
-      document.body.appendChild(privateFrame);
-    });
-  </script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect.html
deleted file mode 100644
index 7c807556826..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect.html
+++ /dev/null
@@ -1,26 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title>mozbrowserlocationchange with final url after redirect</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<body></body>
-<script>
-    async_test(function(t) {
-        var iframe = document.createElement("iframe");
-        iframe.mozbrowser = "true";
-        iframe.src = "redirect_init.html?pipe=status(302)|header(Location,redirect_final.html)";
-        var i = 0;
-        iframe.addEventListener("mozbrowserlocationchange", t.step_func(e => {
-            switch (++i) {
-                case 1:
-                    assert_equals(e.detail.url, "about:blank");
-                    break;
-                case 2:
-                    assert_equals(e.detail.url, new URL("redirect_final.html", location).href);
-                    t.done();
-                    break;
-            }
-        }));
-        document.body.appendChild(iframe);
-    });
-</script>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_final.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_final.html
deleted file mode 100644
index cd059ad53fc..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_final.html
+++ /dev/null
@@ -1 +0,0 @@
-<h1>redirect_final</h1>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_init.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_init.html
deleted file mode 100644
index f6c7e1d9df5..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/redirect_init.html
+++ /dev/null
@@ -1 +0,0 @@
-<h1>redirect_init</h1>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/reload.html b/tests/wpt/mozilla/tests/mozilla/mozbrowser/reload.html
deleted file mode 100644
index 7dea32d3730..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/reload.html
+++ /dev/null
@@ -1,35 +0,0 @@
-<head>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
-<script>
-
-async_test(function(t) {
-
-  const SRC = "data:,foobar";
-  const RELOAD_MAX_COUNT = 5;
-
-
-  var iframe = document.createElement("iframe");
-  iframe.mozbrowser = "true";
-  iframe.src = SRC;
-
-  var reload_count = 0;
-
-  iframe.addEventListener("mozbrowserloadend", t.step_func(e => {
-    reload_count++;
-    assert_equals(SRC, e.target.src);
-    if (reload_count == RELOAD_MAX_COUNT) {
-      t.done();
-    } else {
-      iframe.reload();
-    }
-  }));
-
-
-  document.body.appendChild(iframe);
-});
-
-</script>
-</body>
diff --git a/tests/wpt/mozilla/tests/mozilla/mozbrowser/stash.py b/tests/wpt/mozilla/tests/mozilla/mozbrowser/stash.py
deleted file mode 100644
index 0b8693a9011..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/mozbrowser/stash.py
+++ /dev/null
@@ -1,10 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-
-def main(request, response):
-    if request.method == 'POST':
-        request.server.stash.put(request.GET["id"], request.body)
-        return ''
-    return request.server.stash.take(request.GET["id"])