It's quite hard to get meaningful results with mxr's weird regex search behaviour, however I think there is only one add-on that translates this strings: https://addons.mozilla.org/thunderbird/addon/qirimtatarca-til-destesi-posta/

I can change the regexes to something like "4047[^A-Z0-9]" but I'm not sure whether that would do it. Should we just ignore (remove) all these numeric strings and warn that one author manually?