You can look at the history of Erlang for a similar example. A very crude summary could be that Ericsson developed the language, took it to production, and then they decided to replace it with Java. The people that did the language design convinced management to release Erlang and the VM as FOSS, and then they promptly went and started a company that could use the tooling they'd developed.

I'm aware I'm leaving out a lot of detail, but it's not clear to me what has become public knowledge and what has not and I happen to know some people that were involved.