> Is anyone updating at least the troff versions of the papers? That is,
> if I go with the source, will I get something (more) current?

It varies by paper. Some are updated, some not. The papers on the
compiler suite get some updates, but the 8½ paper not. That paper,
for example, provides a really good view on how one could use the
system principles to construct a window system; the fact that the
current window system is constructed differently doesn't really
change that.

> Well, actually printing is what I had in mind, but maybe I'm being
> too much of a luddite.

Nothing wrong with printing. Having a physical copy of the manual
is invaluable when things go sideways, and reading the papers on
a high-DPI, non-reflective surface is a joy. Since I don't believe
anyone has Plan 9 driving an e-Ink display (anyone? anyone?),
paper does nicely.

> Has anyone tried producing the doc using groff under Linux, or would
> it require a running Plan 9 system to correctly (re)generate everything?

As others have said, I suspect groff will have issues (I have no idea
how to test that locally), but I can confirm that p9p's works as
expected.

Anthony