human friendly, or can not be adequately viewed by plain text pagers.
=> https://en.wikipedia.org/wiki/Plain_Old_Documentation Plain Old Documentation, POD\r
-=> https://docutils.sourceforge.io/rst.html, reStructured Text (reST)\r
+=> https://docutils.sourceforge.io/rst.html reStructured Text (reST)\r
=> https://www.sphinx-doc.org/en/master/ Sphinx\r
=> https://en.wikipedia.org/wiki/Docbook DocBook\r
=> https://asciidoc-py.github.io/index.html AsciiDoc\r