If you aren't familiar, the .git folder contains the files of a repository from github (you have the dead link in the .git/config file) from the translator. The idea is that, if the translation has broken anything, you could return to a backup of the translation saved in the repository to debug different versions and solve the problem. It could also be used to share new versions of the translation.
However, as you can see, the original repo is dead, meaning it could have been moved elsewhere (wouldn't be the first time) or is just plain dead media. So in a way, having the .git folder is a mark of the translator that may be worth keeping to some. If you're weary or don't find it useful (a GB is still a GB), just delete it safely without any seatback. Checked the whole folder for a pointer to the .git just to be sure and did not find anything (as I would expect, this folder should only be accessed by the git command to access it's contents). Why is it so heavy though? My guess is that it contains the whole game instead of only the translation, which is completely unnecessary unless you're modifying art, which if I rememeber correctly, this translation did not.
So yeah, in summary, it's bloat you can get rid off without any worries.