diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 2d91273be15..9220c3b1a66 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -3821,7 +3821,14 @@ impl AliasId {
     }
 }
 
-// NOTE(emilio): Callers are responsible to deal with prefs.
+/// Call the given macro with tokens like this for each longhand and shorthand properties
+/// that is enabled in content:
+///
+/// ```
+/// [CamelCaseName, SetCamelCaseName, PropertyId::Longhand(LonghandId::CamelCaseName)],
+/// ```
+///
+/// NOTE(emilio): Callers are responsible to deal with prefs.
 #[macro_export]
 macro_rules! css_properties_accessors {
     ($macro_name: ident) => {
@@ -3844,6 +3851,14 @@ macro_rules! css_properties_accessors {
     }
 }
 
+/// Call the given macro with tokens like this for each longhand properties:
+///
+/// ```
+/// { snake_case_ident, true }
+/// ```
+///
+/// … where the boolean indicates whether the property value type
+/// is wrapped in a `Box<_>` in the corresponding `PropertyDeclaration` variant.
 #[macro_export]
 macro_rules! longhand_properties_idents {
     ($macro_name: ident) => {
diff --git a/components/style_traits/values.rs b/components/style_traits/values.rs
index 6da235c07b6..582e34eb3db 100644
--- a/components/style_traits/values.rs
+++ b/components/style_traits/values.rs
@@ -158,24 +158,6 @@ where
     }
 }
 
-#[macro_export]
-macro_rules! serialize_function {
-    ($dest: expr, $name: ident($( $arg: expr, )+)) => {
-        serialize_function!($dest, $name($($arg),+))
-    };
-    ($dest: expr, $name: ident($first_arg: expr $( , $arg: expr )*)) => {
-        {
-            $dest.write_str(concat!(stringify!($name), "("))?;
-            $first_arg.to_css($dest)?;
-            $(
-                $dest.write_str(", ")?;
-                $arg.to_css($dest)?;
-            )*
-            $dest.write_char(')')
-        }
-    }
-}
-
 /// Convenience wrapper to serialise CSS values separated by a given string.
 pub struct SequenceWriter<'a, 'b: 'a, W: 'b> {
     inner: &'a mut CssWriter<'b, W>,
@@ -450,7 +432,7 @@ impl_to_css_for_predefined_type!(::cssparser::RGBA);
 impl_to_css_for_predefined_type!(::cssparser::Color);
 impl_to_css_for_predefined_type!(::cssparser::UnicodeRange);
 
-#[macro_export]
+/// Define an enum type with unit variants that each correspond to a CSS keyword.
 macro_rules! define_css_keyword_enum {
     (pub enum $name:ident { $($variant:ident = $css:expr,)+ }) => {
         #[allow(missing_docs)]