It's called Garnet. Supports both Monero and Lightning, but if you prefer Amethyst or another client just put a Monero address somewhere in your profile and any Garnet user can one-click tip any of your notes

There are a few users, but still some work that needs to be done and it's lagging behind a bit on updates

https://github.com/retrnull/garnet

https://bounties.monero.social/posts/147/garnet-maintenance-sync-upstream-new-icons-resolve-amethyst-dual-install-conflict-etc