that in the NetRexx repository the Language Reference is in odf
format but both the guides are in tex?
Yes, I've been in conversation behind
the scenes with René and he confirms your findings: the NRL
remains in its original format (from the day of open sourcing),
while the others are new(ish) and are in LaTeX.
I don't use Open or Libre Office so I can't say (but I doubt) if
either one can process TEX files. There are online compilers if
you get that far and need the services of one (free, of course).
A reasonably complete LaTeX installation will consume a fair chunk
of real estate on your disk drive, and the learning curve is a bit
steep -- but simple edits are pretty easy and rather obvious once
you peek inside (the sources are flat text files, with markup ...
think of HTML and you'll be close).