diff --git a/components/layout_2020/dom_traversal.rs b/components/layout_2020/dom_traversal.rs
index d5494a363bf..05fd5a870a9 100644
--- a/components/layout_2020/dom_traversal.rs
+++ b/components/layout_2020/dom_traversal.rs
@@ -219,7 +219,9 @@ fn traverse_pseudo_element_contents<'dom, Node>(
                 });
                 let display_inline = DisplayGeneratingBox::OutsideInside {
                     outside: DisplayOutside::Inline,
-                    inside: DisplayInside::Flow,
+                    inside: DisplayInside::Flow {
+                        is_list_item: false,
+                    },
                 };
                 // `display` is not inherited, so we get the initial value
                 debug_assert!(
diff --git a/components/layout_2020/flow/construct.rs b/components/layout_2020/flow/construct.rs
index d4151e13c51..908119e98d4 100644
--- a/components/layout_2020/flow/construct.rs
+++ b/components/layout_2020/flow/construct.rs
@@ -30,12 +30,18 @@ impl BlockFormattingContext {
         info: &NodeAndStyleInfo<Node>,
         contents: NonReplacedContents,
         propagated_text_decoration_line: TextDecorationLine,
+        is_list_item: bool,
     ) -> Self
     where
         Node: NodeExt<'dom>,
     {
-        let (contents, contains_floats) =
-            BlockContainer::construct(context, info, contents, propagated_text_decoration_line);
+        let (contents, contains_floats) = BlockContainer::construct(
+            context,
+            info,
+            contents,
+            propagated_text_decoration_line,
+            is_list_item,
+        );
         let bfc = Self {
             contents,
             contains_floats: contains_floats == ContainsFloats::Yes,
@@ -97,7 +103,11 @@ enum BlockLevelCreator {
 /// Deferring allows using rayon’s `into_par_iter`.
 enum IntermediateBlockContainer {
     InlineFormattingContext(InlineFormattingContext),
-    Deferred(NonReplacedContents, TextDecorationLine),
+    Deferred {
+        contents: NonReplacedContents,
+        propagated_text_decoration_line: TextDecorationLine,
+        is_list_item: bool,
+    },
 }
 
 /// A builder for a block container.
@@ -164,6 +174,7 @@ impl BlockContainer {
         info: &NodeAndStyleInfo<Node>,
         contents: NonReplacedContents,
         propagated_text_decoration_line: TextDecorationLine,
+        is_list_item: bool,
     ) -> (BlockContainer, ContainsFloats)
     where
         Node: NodeExt<'dom>,
@@ -180,6 +191,10 @@ impl BlockContainer {
             contains_floats: ContainsFloats::No,
         };
 
+        if is_list_item {
+            // FIXME: generate a box for the list marker
+        }
+
         contents.traverse(context, info, &mut builder);
 
         debug_assert!(builder.ongoing_inline_boxes_stack.is_empty());
@@ -390,7 +405,9 @@ where
         display_inside: DisplayInside,
         contents: Contents,
     ) -> ArcRefCell<InlineLevelBox> {
-        let box_ = if display_inside == DisplayInside::Flow && !contents.is_replaced() {
+        let box_ = if let (DisplayInside::Flow { is_list_item }, false) =
+            (display_inside, contents.is_replaced())
+        {
             // We found un inline box.
             // Whatever happened before, all we need to do before recurring
             // is to remember this ongoing inline level box.
@@ -402,6 +419,10 @@ where
                 children: vec![],
             });
 
+            if is_list_item {
+                // FIXME: generate a box for the list marker
+            }
+
             // `unwrap` doesn’t panic here because `is_replaced` returned `false`.
             NonReplacedContents::try_from(contents)
                 .unwrap()
@@ -485,9 +506,15 @@ where
 
         let kind = match contents.try_into() {
             Ok(contents) => match display_inside {
-                DisplayInside::Flow => BlockLevelCreator::SameFormattingContextBlock(
-                    IntermediateBlockContainer::Deferred(contents, propagated_text_decoration_line),
-                ),
+                DisplayInside::Flow { is_list_item } => {
+                    BlockLevelCreator::SameFormattingContextBlock(
+                        IntermediateBlockContainer::Deferred {
+                            contents,
+                            propagated_text_decoration_line,
+                            is_list_item,
+                        },
+                    )
+                },
                 _ => BlockLevelCreator::Independent {
                     display_inside,
                     contents: contents.into(),
@@ -695,9 +722,17 @@ impl IntermediateBlockContainer {
         Node: NodeExt<'dom>,
     {
         match self {
-            IntermediateBlockContainer::Deferred(contents, propagated_text_decoration_line) => {
-                BlockContainer::construct(context, info, contents, propagated_text_decoration_line)
-            },
+            IntermediateBlockContainer::Deferred {
+                contents,
+                propagated_text_decoration_line,
+                is_list_item,
+            } => BlockContainer::construct(
+                context,
+                info,
+                contents,
+                propagated_text_decoration_line,
+                is_list_item,
+            ),
             IntermediateBlockContainer::InlineFormattingContext(ifc) => {
                 // If that inline formatting context contained any float, those
                 // were already taken into account during the first phase of
diff --git a/components/layout_2020/formatting_contexts.rs b/components/layout_2020/formatting_contexts.rs
index 0ec2bf1144c..a311eb8a3a2 100644
--- a/components/layout_2020/formatting_contexts.rs
+++ b/components/layout_2020/formatting_contexts.rs
@@ -71,13 +71,15 @@ impl IndependentFormattingContext {
         match contents.try_into() {
             Ok(non_replaced) => {
                 let contents = match display_inside {
-                    DisplayInside::Flow | DisplayInside::FlowRoot => {
+                    DisplayInside::Flow { is_list_item } |
+                    DisplayInside::FlowRoot { is_list_item } => {
                         NonReplacedFormattingContextContents::Flow(
                             BlockFormattingContext::construct(
                                 context,
                                 info,
                                 non_replaced,
                                 propagated_text_decoration_line,
+                                is_list_item,
                             ),
                         )
                     },
diff --git a/components/layout_2020/style_ext.rs b/components/layout_2020/style_ext.rs
index 9aa2ea73160..58551aedbe6 100644
--- a/components/layout_2020/style_ext.rs
+++ b/components/layout_2020/style_ext.rs
@@ -33,7 +33,6 @@ pub(crate) enum DisplayGeneratingBox {
     OutsideInside {
         outside: DisplayOutside,
         inside: DisplayInside,
-        // list_item: bool,
     },
     // Layout-internal display types go here:
     // https://drafts.csswg.org/css-display-3/#layout-specific-display
@@ -47,8 +46,10 @@ pub(crate) enum DisplayOutside {
 
 #[derive(Clone, Copy, Eq, PartialEq)]
 pub(crate) enum DisplayInside {
-    Flow,
-    FlowRoot,
+    // “list-items are limited to the Flow Layout display types”
+    // https://drafts.csswg.org/css-display/#list-items
+    Flow { is_list_item: bool },
+    FlowRoot { is_list_item: bool },
     Flex,
 }
 
@@ -444,8 +445,12 @@ impl ComputedValuesExt for ComputedValues {
 impl From<stylo::Display> for Display {
     fn from(packed: stylo::Display) -> Self {
         let inside = match packed.inside() {
-            stylo::DisplayInside::Flow => DisplayInside::Flow,
-            stylo::DisplayInside::FlowRoot => DisplayInside::FlowRoot,
+            stylo::DisplayInside::Flow => DisplayInside::Flow {
+                is_list_item: packed.is_list_item(),
+            },
+            stylo::DisplayInside::FlowRoot => DisplayInside::FlowRoot {
+                is_list_item: packed.is_list_item(),
+            },
             stylo::DisplayInside::Flex => DisplayInside::Flex,
 
             // These should not be values of DisplayInside, but oh well
@@ -459,11 +464,7 @@ impl From<stylo::Display> for Display {
             // This should not be a value of DisplayInside, but oh well
             stylo::DisplayOutside::None => return Display::None,
         };
-        Display::GeneratingBox(DisplayGeneratingBox::OutsideInside {
-            outside,
-            inside,
-            // list_item: packed.is_list_item(),
-        })
+        Display::GeneratingBox(DisplayGeneratingBox::OutsideInside { outside, inside })
     }
 }
 
diff --git a/components/style/values/specified/box.rs b/components/style/values/specified/box.rs
index aeebc999261..4519a60aaa0 100644
--- a/components/style/values/specified/box.rs
+++ b/components/style/values/specified/box.rs
@@ -520,9 +520,7 @@ fn is_valid_inside_for_list_item<'i>(inside: &Result<DisplayInside, ParseError<'
 
 /// Parse `list-item`.
 fn parse_list_item<'i, 't>(input: &mut Parser<'i, 't>) -> Result<(), ParseError<'i>> {
-    Ok(try_match_ident_ignore_ascii_case! { input,
-        "list-item" => (),
-    })
+    Ok(input.expect_ident_matching("list-item")?)
 }
 
 impl Parse for Display {