(Double posted, so reply to your list)
What's going on with Linux kernel?
v6.18 was just released, and it's moving to v6.19.
On the oft chance that this is not a joke question. The linux kernel has a release cycle ~8-10 weeks long. v6.18 came out on Nov 30, which means Dec 14 the merge window for 6.19 closed and the first rc was released. Every Sunday following that. Linus will release a new rc till he is satisfied that it is stable enough (generally rc7 to rc8) and then a final release will be tagged.
Dhaval