Load as a Vim plugin. E.g. when using vim-plug, add to ~/.vimrc:

Plug 'z-shell/zi-vim-syntax'

and then issue the :PlugInstall command.

To install the syntax copy the file after/syntax/zsh.vim under the path ~/.vim/syntax/after.

The default theme:

The theme flrnprz/plastic.vim:

The theme slate:

The theme murphy:

The theme lucasprag/simpleblack:

1. Highlight user and plugin with different colors.
2. Make the wait's distinctness controlled.
3. Make the syntax matching commands fully contained.
4. Fix bugs.
5. Other?