Yes, I can;t find any documentation online about RevisionRepository, either. There are no samples or Java docs anywhere. If the people working on Spring have something in Spring that is undocumented, it usually means that this is something that they are working on and are not ready to release to the world, or this is an internal interface/class that they don't want to be exposed. There's nothing stopping you from using an undocumented feature of Spring, of course. However, if you do want to use it, it usually means you will have to dig into the Spring Data code yourself and reverse engineer the code, OR get in touch with the creators and volunteer to make enhancements
However, the larger question is, what are you trying to do that is leading you towards an undocumented feature of Spring? Maybe you could do it some other way?