[0x0]

Why not? The article claimed it modified a .php file. So I'm curious to know if it would modify the equivalent file under .git/objects?

[Dylan16807]

Because the equivalent file is either compressed with a custom header or in a totally-incomprehensible-to-it binary pack.

Let me put it this way: I would be scared to store an svn checkout because of how svn stores metadata copies. I wouldn't worry about a git checkout.