Not sure who is still using the Special Fields add-on, but I still had it vestigially from years ago and have submitted a PR fixing and updating it for Anki 26.09+. If the AH team is maintaining that repo, I would appreciate a look at it Fix for anki 26.09+ by jason-s-yu · Pull Request #47 · johnpincock/SpecialFields · GitHub so that the AnkiWeb addon page can be updated.
That’s reasonable. I’m happy to maintain the add-on in the meantime. It might be nonetheless good to merge the fix and deploy a fix and put a note on the addon itself on ankiweb.