I really have no idea. I work only with small or at most medium sized companies. All of them put their code on a git server they don't own. All of them are concerned about AI companies looking at their code. They hope that at least they won't train their models with their code if they pay.

I think that the reasoning is: they trust the git company (whatever it is) not to sell their code. They are worried that their code goes into a model and somebody else could ask the model "write a service like XYZ" and it will regurgitate their code.

No, they run GitLab because GitHub Enterprise is a horrible thing nobody has ever said a good thing about.

GitLab even has a free self-hosted version, and it has a number of advantages (like being able to actually have a structure with inherited secrets and accesses, and no, GitHub Organisations do not count and suck). And for years thanks to GitLab-CI it was clearly ahead.