Linux 5.14 changelog.
It will take some time to complete this page, sorry. Meanwhile, you can take a look at the list of changes in LWN: https://lwn.net/Articles/867706/
Also, take a look at their detailed merge window summaries:
Merge [[https://lwn.net/Articles/861248/|window part 1]
Merge [[https://lwn.net/Articles/861695/|window part 2]