Consider manage patched and unpatched fonts using git LFS to reduce repo size? 
the reason this repo too large is because of font files, especially patched fonts, consider using git-lfs to track them and rewrite history will resolve this problem. the only side effect is need to force push whole rewrited history and the upload lfs objects will take a huge time but only the first time, and everyone may be need to reclone the repo. but the repo size will decrease to a vary small size. 