This manual is written in LATEXinfo. LATEXinfo is a documentation system that uses a single source file for both on-line documentation and a printed manual. See the LATEXinfo Manual for more details [].
The on-line documentation is in the form of an Info file. An on-line Info file is a file formatted so that the Info documentation reading program can operate on it. Info files are divided into pieces called nodes, each of which contains the discussion of one topic. M-x info in emacs and xinfo under X11 are two Info documentation reading programs that can be used for on-line manipulation of this manual.