The 6.15 kernel has been released
So this was delayed by a couple of hours because of a last-minute bug report resulting in one new feature being disabled at the eleventh hour, but 6.15 is out there now.
Significant changes in 6.15 include smarter timer-ID assignment to make checkpoint/restore operations more reliable, the ability to read status information from a pidfd after the process in question has been reaped, the PIDFD_SELF special pidfd value, nested ID-mapped mounts, zero-copy network-data reception via io_uring, The ability to read epoll events via io_uring, resilient queued spinlocks for BPF programs, guard-page enhancements allowing them to be placed in file-backed memory areas and for user space to detect their presence, the once-controversial fwctl subsystem, the optional sealing of some system mappings, and much more.
See the LWN merge-window summaries (part 1, part 2) and the in-progress KernelNewbies 6.15 page for more information.