There are multiple ones actually. On prismo I haven't seen any work being done in a while (more than half a year according to the repo you linked :D). I think

There are multiple ones actually. On prismo I haven't seen any work being done in a while (more than half a year according to the repo you linked :D). I think the dev got a bit discouraged after his instance had a data loss problem. It used to be at https://prismo.xyz https://prismo.xyz but seems to be down. One which is pretty active (development wise) is https://dev.lemmy.ml https://dev.lemmy.ml. But they don't have federation yet either.