diff --git a/pyproject.toml b/pyproject.toml
index b64556553b..09b6cd94fe 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -195,6 +195,7 @@ extend-exclude = '''
 # in the root of the project. Separate regexes with | .
 (
     .*_pb2.py  # exclude autogenerated Protocol Buffer files anywhere in the project
+    |^/Lib/fontbakery/legacy_checkids.py
 )
 '''