Things continue to look fairly normal, with rc3 being larger than rc2, as people are starting to find more regressions, but 5.4 so far remains on the smaller side of recent releases.
The diffstat looks fairly flat too, although we had a couple of staging drivers being removed here that show up as spikes. Drivers in general account for about two thirds of the diff, and it's not just those staging drivers, it's other small noise all over the place: usb, drm, iio, rdma..
Outside of drivers, filesystems pop up more than perhaps usual, but it's again mostly low-grade noise all over: btrfs, cifs, nfs, ocfs, xfs and some core vfs fixes.
The rest is arch updates (mainly arm64, x86, mips), tooling (mostly perf tooling updates, but also some selftest fixlets), documentation, and misc core kernel and mm stuff.
There really isn't anything huge that stands out. You can scan the appended shortlog for a flavor of the details, it's not too long to just scroll through.