I'm not familiar with the git extension, what happens if you don't have it installed. Will the pointer files get in the way of extracting the .zip files?
If they can peacefully coexist, the we could have both options available. Then no one would be _required_ to install an extension.
Although that does raise another point in my mind... I had assumed the git repo would be there in addition to a separate source download (rather than replacing it), is that the case? Would a new heroite be required to install git to get the source?