It's still actively developed. https://github.com/parse-community/parse-server

Yes, it was a fairly popular BaaS offering during 2014-2016

https://insights.stackoverflow.com/trends?tags=parse-platfor...

It was definitely popular. It used to be the go to solution on r/AndroidDev for people wanting a simple backend solution without having much experience. Everyone switched to Google Firebase after Facebook shut it down.