diff --git a/ed/idlpatches/css-fonts.idl.patch b/ed/idlpatches/css-fonts.idl.patch
new file mode 100644
index 000000000000..7f8f1083d59d
--- /dev/null
+++ b/ed/idlpatches/css-fonts.idl.patch
@@ -0,0 +1,64 @@
+From bcdc9b8557f43afda25b97c8b873285efe2ff78b Mon Sep 17 00:00:00 2001
+From: Francois Daoust <fd@tidoust.net>
+Date: Tue, 14 Jan 2025 11:06:56 +0100
+Subject: [PATCH] Drop interfaces redefined in css-fonts-5
+
+The `CSSFontFaceDescriptors` and `CSSFontFaceRule` interfaces get redefined in
+CSS Fonts Level 5, creating duplicates. The patch will likely be needed until
+CSS Fonts Level 5 becomes a full spec.
+---
+ ed/idl/css-fonts.idl | 38 --------------------------------------
+ 1 file changed, 38 deletions(-)
+
+diff --git a/ed/idl/css-fonts.idl b/ed/idl/css-fonts.idl
+index d5c9dc867..9b8034bc6 100644
+--- a/ed/idl/css-fonts.idl
++++ b/ed/idl/css-fonts.idl
+@@ -3,44 +3,6 @@
+ // (https://github.com/w3c/webref)
+ // Source: CSS Fonts Module Level 4 (https://drafts.csswg.org/css-fonts-4/)
+ 
+-[Exposed=Window]
+-interface CSSFontFaceDescriptors : CSSStyleDeclaration {
+-  attribute [LegacyNullToEmptyString] CSSOMString src;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontFamily;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-family;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontStyle;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-style;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontWeight;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-weight;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontStretch;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-stretch;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontWidth;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-width;
+-  attribute [LegacyNullToEmptyString] CSSOMString unicodeRange;
+-  attribute [LegacyNullToEmptyString] CSSOMString unicode-range;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontFeatureSettings;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-feature-settings;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontVariationSettings;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-variation-settings;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontNamedInstance;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-named-instance;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontDisplay;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-display;
+-  attribute [LegacyNullToEmptyString] CSSOMString fontLanguageOverride;
+-  attribute [LegacyNullToEmptyString] CSSOMString font-language-override;
+-  attribute [LegacyNullToEmptyString] CSSOMString ascentOverride;
+-  attribute [LegacyNullToEmptyString] CSSOMString ascent-override;
+-  attribute [LegacyNullToEmptyString] CSSOMString descentOverride;
+-  attribute [LegacyNullToEmptyString] CSSOMString descent-override;
+-  attribute [LegacyNullToEmptyString] CSSOMString lineGapOverride;
+-  attribute [LegacyNullToEmptyString] CSSOMString line-gap-override;
+-};
+-
+-[Exposed=Window]
+-interface CSSFontFaceRule : CSSRule {
+-  [SameObject, PutForwards=cssText] readonly attribute CSSFontFaceDescriptors style;
+-};
+-
+ partial interface CSSRule {  const unsigned short FONT_FEATURE_VALUES_RULE = 14;
+ };
+ [Exposed=Window]
+-- 
+2.37.1.windows.1
+