--- a/python/mozbuild/mozbuild/frontend/data.py
+++ b/python/mozbuild/mozbuild/frontend/data.py
@@ -1185,16 +1185,17 @@ class GeneratedFile(ContextDerived):
             '.cpp',
             '.h',
             '.inc',
             '.py',
             '.rs',
             'node.stub', # To avoid VPATH issues with installing node files: https://bugzilla.mozilla.org/show_bug.cgi?id=1461714#c55
             'android_apks', # We need to compile Java to generate JNI wrappers for native code compilation to consume.
             '.profdata',
+            '.webidl'
         )
         self.required_for_compile = [f for f in self.outputs if f.endswith(suffixes) or 'stl_wrappers/' in f]
 
 
 class ChromeManifestEntry(ContextDerived):
     """Represents a chrome.manifest entry."""
 
     __slots__ = (