Good question, I'd say this was mostly a community initiative for the last decade, but a couple Apple employees have been pitching in a bit lately also. There is an Apple employee on the official Android workgroup, and we have been communicating with the core team and other Swift steering groups for the last couple years on how to move this Android port forward.
Many Apple employees have contributed their time to reviewing our Android pull requests for the last decade, so I'd like to thank them all for that. 