[tldoc] suggestions for the doc section 3.4.5 context lmtx and mkiv

[Karl Berry]

Hi again Carlos,

    Both LuaLaTeX and ConTeXt are included. Correct?

I don't actually know if lualatex and context have the same behavior or
use the same variables any more, even though it is so stated.

    reason: presumably because of the kpathsea library.

Kpathsea has nothing to do with this issue. It's all in the Lua code in
the respective packages. As far as kpathsea is concerned, TEXMFVAR,
TEXMFSYSVAR, and TEXMFCACHE (and many other vars) are just generic
variables that could be named foo, bar, and baz.

    Anyway. Here's a possible draft for the doc, and from what I've seen 

Thanks, but I simply don't think the TL guide is the place to go into
these details of behavior, which may or may not change at any time. And,
more importantly, about which there is, apparently, nothing the user can
or should do.

    +or
    +\begin{sverbatim}
    +mtxrun --generate
    +\end{sverbatim}

As far as I know, it's not "or". At least, what tlmgr and install-tl
actually do is run both commands.

The current text says, in effect, "there's nothing to do by default, but
if you install files manually, then run the cache commands". That seems
to me like all there is to say. If the behavior needs to be improved,
that should be done by default, not by (in principle) every TL user
changing the configuration.

Yes, there are hundreds of lines of output from the commands, but users
don't actually have to do anything about any of it, as far as I
know. --best, karl.