> [...'less /kern/msgbuf' vs 1.6 or current...]

/kern/msgbuf is poorly implemented; it does not work quite like the
file it appears to be.  I ran into this a while ago with "tail" (IIRC
the issue there was mmap(2), and I _think_ it was fixed).

Personally, I'd say it's worth a PR if it's still present.

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