I get the following when I start my Zsh.
Usage: prompt <options>
Options:
-c Show currently selected theme and parameters
-l List currently available prompt themes
-p [<themes>] Preview given themes (defaults to all)
-h [<theme>] Display help (for given theme)
-s <theme> Set and save theme
<theme> Switch to new theme immediately (changes not saved)
It seems to be set by some theme file, since the same text is here.
How can you disable the notification in Zsh?