We discussed it back in March and here are some numbers for the bitcoin core repo:
tbh those numbers are not that big. last time I checked, git implementations in the browser don't support these advanced flags. doing a full clone automatically in the browser is probably a bad idea as it is unfair on those who are bandwidth constrained.
But this could be done statelessly on a server fairly quickly. bandwidth on a VPS is probably quite cheap these days so if traffic volumes were low it shouldn't be too expensive.
Depending on the bandwidth vs storage costs it could be worth storing a clone of repositories and using that instead. That way it would be easier, or cheaper per interaction, to allow browsing commits, metadata, etc.
From a decentralisation point of view, I could build `ngit serve` which could be used instead (even in offline scenarios) instead of the proxy.