Arch and Manjaro recently updated to Python 3.14 which is not compatable with your internal parser.
I ran across it while trying to use the cssUndefinedClasses plugin which uses the parser.
I found a fix for it here however: (This is from the standalone gumbo-parser Arch uses)
make EnumMetaclass compatible with Python 3.13
https://codeberg.org/gumbo-parser/gumbo-parser/commit/b7dfdeb84937fbc8fe719a6d0bd7bfd0fa8e7683
Arch and Manjaro recently updated to Python 3.14 which is not compatable with your internal parser.
I ran across it while trying to use the cssUndefinedClasses plugin which uses the parser.
I found a fix for it here however: (This is from the standalone gumbo-parser Arch uses)
make EnumMetaclass compatible with Python 3.13
https://codeberg.org/gumbo-parser/gumbo-parser/commit/b7dfdeb84937fbc8fe719a6d0bd7bfd0fa8e7683