This is a repository that has been packed over time with "git gc", but repacks from ~245M to ~145M with "git gc --aggressive". To narrow it down, I tried different packing options. With each of the following commands, I get these resulting pack sizes:
git repack -ad: 246Mgit repack -ad -f: 376Mgit repack -ad --window=250: 246Mgit repack -ad -f --window=250: 145M