I don't think there's a need to erase copyrighted material? If it's your material then the copyright still holds. If it's not your material it's a problem bet

I don't think there's a need to erase copyrighted material? If it's your material then the copyright still holds. If it's not your material it's a problem between GitHub and the copyright holder who can DMCA the "hidden commit" if for some godforsaken reason the copyright holder somehow found the commit and cares.