Zsh

ZSH is a shell, it is almost entirely backwards compatible with bash with several additional options.

Documentation

official docs	http://zsh.sourceforge.net/Doc/Release/index-frame.html
zsh manpages	https://manpages.debian.org/buster/zsh-common/index.html

Locations

~/.zshrc	rcfile
/usr/share/zsh/functions/Completion/*/*	builtin completions (see $fpath)
/usr/share/zsh/site-functions	third party zsh completions

Components

ZLE	man zshzle	zsh's line editor
compctl	man zshcompctl	old completion system
compsys	man zshcompsys	new completion system
compwid	man zshcompwid

See man zsh and man zshroadmap for overviews.

Notes

zsh antigen

zsh plugins

zsh autocompletion