Zsh Bindkey Table
Zsh Line Editor
If the ZLE option is set (it is by default) and the shell input is attached to the terminal, the user is allowed to edit command lines.
There are two display modes. The first, multi-line mode, is the default. It only works if the TERM parameter is set to a valid terminal type that can move the cursor up. The second, single line mode, is used if TERM is invalid or incapable of moving the cursor up, or if the SINGLE_LINE_ZLE option is set. This mode is similar to ksh, and uses no termcap sequences. If TERM is emacs', the ZLE` option will be unset by the shell.