The last "full release" of GameSense was v2.3.0, which can be downloaded from the releases page or as an actions build. A "development release" can also be downloaded and the source can be viewed in the d2.3.1 branch.
The discord can still be joined here, however no support will be given but things such as a usage tutorial and configurations are still up. Several people have made continuations of the client, public and private, which are not affiliated with this main repo or myself, IUDevman. If you're looking for a client that is still being actively developed, I recommend Cosmos.
Feel free to check through the history of this README file to find some old information about the client.