jj is not "one guy who works at Google" and the vast majority of submitted code comes from non-Google developers. Even if Google were to stop developing jj (they won't) the project would be healthy and strong.

There's some legal annoyances around e.g. CLA which was a result of being a side project of Google originally. Hopefully we'll move through that in due time. But realistically it's a much larger project at this point and has grown up a lot, it's not Martin's side project anymore.

That hasn't really been the case for a while imo: Martin works at Google and is paid to work on jj (there are also other Google employees who contribute, not sure whether they're paid to). jj is in use (wide use? No idea) alongside Google's internal tool (piper) with which it can interact (and with which it has some features in common) because jj has a pluggable backend architecture.

While I hate to engage in speculation, tell spooky stories, or screech at people about the evil CLA you have to sign in order to contribute, my personal opinion is that if Google were ever to start throwing their weight around, the project would be forked in short order and development would continue as normal – it has momentum, plenty of non-Google contributors, and a community. It's also not a product per se, though as we're about to find out, you can certainly build products on top of it – that probably makes it less likely for its current home to suddenly become proprietorial about it.

(hi Andy!)