texinfo - 6.5.0.dfsg.1-4+b1 main

Texinfo is a documentation system that uses a single source file to
produce both on-line information and printed output.
.
Using Texinfo, you can create a printed document with the normal features
of a book, including chapters, sections, cross references, and indices.
From the same Texinfo source file, you can create a menu-driven, on-line
Info file with nodes, menus, cross references, and indices.