So we probably didn't strictly need an rc8 this release, but with LPC and the KS conference travel this upcoming week it just makes everything easier.
And partly because of the extra week, we then had a few fixes that maybe otherwise would have been delayed and marked for stable. The most notable one (but hopefully not very noticeable) is fixing race conditions in configfs. That won't affect very many people, with configfs not all that widely used, but Christoph and Al both felt it needed to be fixed.
Other than that, it really is a very small rc (and hopefully the final week will be smaller still). In fact, the configfs fix along with a vhost revert is about half of the patch. The rest is various small things: a few sound fixes, some drm fixes, and a few other random fixes. Even in the drm case, the selftest addition is bigger than the core code patches.
The appended shortlog is short enough that it's easy enough to scroll through if you are interested in the details.