More than halt the rc2 patch is actually Documentaiton updates, because the kvm docs got turned into RST.
Another notable chunk is just tooling updates, which is about 50/50 perf updates (much of it due to header file syncing) and - again - kvm updates.
But if you ignore those parts, and look at only the actual kernel code updates, things look a bit calmer. The bulk ends up being network driver updates (intel "ice" driver - E800 series - stands out) with GPU updates a close second (i915, amd, panfrost). There's a few other driver updates in there too, but they are mostly hidden in the noise compared to the network and gpu subsystems: rdma, sound, acpi, block, gpio etc.
Outside of drivers, there's the usual smattering of changes all over. Filesystems (nfs, ext4, ceph, cifs, btrfs), architecture updates (x86, arm), and some core code (scheduling, tracing, networking, io_uring).
The shortlog is appended, you can get a feel for the details by scanning it.