@QuiveryNut Welcome to the Rockstor community forum.
Re:
This one is easy. We have not yet released a Stable rpm (repository) for Leap 15.4, but we are getting there. As of this post we are on our Release Candidate 3 (RC3) in the testing channel, which is also included in our most recent downloadable installers:
And the repo will just be skipped as a result, at least untill it actualy exists, as indicated by the:
We have the following GitHub milestone for our next stable release: