From the godfather Himself:

I'd like to point out (yet again) that we don't do feature-based releases, and that "5.0" doesn't mean anything more than that the 4.x numbers started getting big enough that I ran out of fingers and toes.

https://lwn.net/Articles/781206/

From kernel.org:

Does the major version number (4.x vs 5.x) mean anything?

No. The major version number is incremented when the number after the dot starts looking "too big." There is literally no other reason.

https://www.kernel.org/releases.html#does-the-major-version-number-4-x-vs-5-x-mean-anything

$ uname -srv Linux 6.18.0-kbal #111 SMP PREEMPT Mon Dec 1 10:26:08 EST 2025

Ah yes that's all fine but the real secret is the meaning of that #111. (I only thought to find out a couple days ago — apparently I've done 111 kernel builds on this machine.)