For offline documentation, I use these in order of preference: • Info¹ documentation, which I read directly in Emacs. (If you have ever used the terminal-based

For offline documentation, I use these in order of preference: • Info¹ documentation, which I read directly in Emacs. (If you have ever used the terminal-based standalone “info” program, please try to forget all about it. Use Emacs to read Info documentation, and preferably use a graphical Emacs instead of a terminal-based one; Info documentation occasionally has images.) • Gnome Devhelp². • Zeal³ • RFC archive⁴ dumps provided by the Debian “doc-rfc“ package⁵. 1. https://www.gnu.org/software/emacs/manual/html_node/info/ https://www.gnu.org/software/emacs/manual/html_node/info/ 2. https://wiki.gnome.org/Apps/Devhelp https://wiki.gnome.org/Apps/Devhelp 3. https://zealdocs.org/ https://zealdocs.org/ 4. https://www.rfc-editor.org/ https://www.rfc-editor.org/ 5. https://tracker.debian.org/pkg/doc-rfc https://tracker.debian.org/pkg/doc-rfc