This video demonstrates the power of M-x outline-minor-mode in GNU Emacs editor.

GNU Free Documentation License

Copyright © 2021-05-10 11:07:15.637414+02 by Jean Louis. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License"