The file xii-lat.tex
would be found, if it were installed below TDS:tex/plain/
. But the TDS specification (or CTAN version without links) writes:
3.1 Macros
TeX macro files shall be stored in separate directories, segregated by
TeX format and package name (we use "format" in its traditional TeX
sense to mean a usefully \dump
-able package):
texmf/tex/⟨format⟩/⟨package⟩/
⟨format⟩ is a format name (examples: amstex
, latex
, plain
,
texinfo
).
The directory tree below TDS:tex/
contains macro files like LaTeX classes, packages or plain macro files. It should be small, to avoid loading/parsing large hierarchies, when compiling a TeX document.
A better place is below TDS:doc/
. From the specification:
3.7 Documentation
Most packages come with some form of documentation: user manuals,
example files, programming guides, etc. In addition, many independent
files not part of any macro or other package have been created to
describe various aspects of the TeX system. The TDS specifies that
these additional documentation files shall be stored in a structure
that parallels to some extent the fonts and tex directories, as
follows:
texmf/doc/⟨category⟩/...
It is also the place for example files, and test files, source code for the documentation, ...
Therefore, the current place below TDS:doc/plain
looks correct for me.
A place for discussing is AFAIK the TeX live mailing list.
texdoc xii
works.texdoc xii
andtexdoc xii-lat
just result in aREADME.txt
file.