Edit: removed a part about ForgeFed which I thought was what I had in mind, and they do a lot of things that would be nice to have (slightly more convenient than just "login with GitHub")... except search which you can't simply work around by creating an account on each git server where you want to contribute. Not sure what part of their project is discovery and why NLnet granted them money under the "Next Generation Search and Discovery" fund which, from the description, is very clearly aimed at search.