prefs: [
  "dom_serviceworker_enabled:true",
  "dom_servo_helpers_enabled:true",
  "dom_testbinding_enabled:true",
  "dom_testbinding_prefcontrolled_enabled:false",
  "dom_testbinding_prefcontrolled2_enabled:true",
  "dom_testbinding_preference_value_falsy:false",
  "dom_testbinding_preference_value_quote_string_test:\"test\"",
  "dom_testbinding_preference_value_space_string_test:test1 test2",
  "dom_testbinding_preference_value_string_empty:",
  "dom_testbinding_preference_value_string_test:test",
  "dom_testbinding_preference_value_truthy:true",
  "media_testing_enabled:true",
]