I see squeeze on Transifex but i cant seem to find it in Xfce. Also not with apt search squeeze. So i cant test the translation. Seems like the last release was 11 years ago and the pot file says: "POT-Creation-Date: 2007-04-24 23:59+0200\n" So in case this software is not going to see new releases maybe it would be better to remove the translations from Transifex so that people dont waste time translating/improving something that is never going to be used.
Good catch, done, squeeze is not maintained anymore and will be archived.