GCC configuration data, perhaps: before it was correct as it was referring to the command and rendered as gcc(1), but now it means the product itself, which name is an abbreviation and thus should be capitalized.

I would have also expanded what those pc files are, currently it's unclear unless the reader already knows what they are.

Come to think of it, I'm not sure what they are for. Compiler and linker options for contributed base software?

I'm not sure what they are for.

man pc(5) -- actually, changing it to .Xr pc 5 would probably be sufficient and avoid the need for elaborate explanation.

Not in base. But perhaps "compiler flags, linker flags, and other information relevant to library use"? (Summarized from first paragraph of https://www.freebsd.org/cgi/man.cgi?query=pc&apropos=0&sektion=0&manpath=FreeBSD+13.1-RELEASE+and+Ports&arch=default&format=html description, as I think it would apply to use in base.)

I forgot that one. Unless there's another round of reviewing, I'll fix it before pushing.

How does it look now?

How does it look now?

Description is okay, but why not annotate .Xr pc 5 explicitly?

Because, as I mentioned earlier, that manual page isn't in base. I'm trying to bring mandoc -T lint complaints down here, not give it more things to complain about.

I doubt this will appease mandoc -T lint, but you could always add a reference that the manual is part of a third-party package, such as in security(7):

security.7:.Xr xterm 1 Pq Pa ports/x11/xterm

WFM.