AFAICT the core of Fig isn't open source. (Why else would there be a waiting list for Linux users if they could just grab the code for Fig and build it themselv

AFAICT the core of Fig isn't open source. (Why else would there be a waiting list for Linux users if they could just grab the code for Fig and build it themselves?) What you are looking at seems to be a repository of autocompletion specs and some server to publish them.