The manual is written in texinfo, so you may want to read
that manual. The stumpwm.texi.in is processed by StumpWM with
some additional markup in the form of three letter character entries
at the beginning of a line. @@@ function defines functions,
%%% some-macro expands to that macro and its docstring, etc.
Contributors are strongly encouraged to add these items to this manual
whenever something new is defined in a patch. You can test if your
texinfo edits are valid by generating them with
make stumpwm.info, and viewing the new stumpwm.info with
info -f /path/to/stumpwm.info, or make
stumpwm.texi for the raw stuff.