I dont know dude, I work in an enormous company that you 've heard of, and it's impossible for me to imagine how to extract code out. I can't do it, except if I get remote access and film my screen while scrolling.
Anything else is found quickly. I certainly wouldn't even dream of someone extracting the repo.
Really, you can't simply copy files from a code repo you're working on? You work on a isolated workstation, not connected to any external network, where you are not allowed to bring anything other than plain clothes (TSA-style)? With a sizable army of developers all working this way?
And if it's a remote FB/VNC connection, what is preventing you from just recording the screen? Not really hard...
Most companies I've seen could see all their code extracted with one malformed NFS packet. These are "air gapped" systems holding the type of industrial secrets that we don't want to leak to china. Practically the only real line of defense they have is employee screening, which does not really stop the lone man guy.
Anything else is found quickly. I certainly wouldn't even dream of someone extracting the repo.