What is Texinfo?
Texinfo is a documentation system that uses one source file to produce both on-line information and printed output. So instead of writing two different documents, one for the on-line help and the other for a typeset manual, you need write only one document source file. When the work is revised, you need only revise one document. You can read the on-line information, known as an “Info file”, with an Info documentation-reading program.