A nice thing about Git is that you can trivially push to a new upstream any time you need.

Yes yes yes, we know. Git is decentralised, you can just trivially push* anywhere!

* - the code. Just the code. only the code. Nothing but the code. You don't need the issues, the roadmap, the ACL of which human can do what, the API access keys for third parties, the artifact repos. Just. The. Code.

Somewhat arsey in my tone? Yeah. But having done two large scale (100+ repos) forge migrations of our company's client projects (SVN -> github, then later on github -> bitbucket) and seeing people completely ignore the metadata surrounding the code that isn't as easy to "just push" anywhere, somewhat justified.