Google's Developer Tooling: Internal or External?

There is a kind of like a pre handover, but that doesn't just mean that the software engineers, the software engineers are done. They still have an on-call rotation and things like that. So yeah, that's... Is it internal or is there a tool that you know, or recommend? Mostly internal stuff. There are efforts to kind of like move away. I believe like the lead maintainer of Git works at Google now or has for a while.