> 
> This is why the documentation for the PATH_SCRIPT option in zshoptions(1) points you to the INVOCATION section of the main zsh manual: the option is really only useful when specified on the command line.
> 

I’ve got lots of quibbles with how that section is written. It is not for mere mortals.Take just the first sentence, for example:

"The following flags are interpreted by the shell when invoked to determine where the shell will read commands from:"

“when invoked” is bad jargon. The use of passive voice is confusing and “to determine where the shell will read commands from” is just torturous wording.

Instead:

A user or script can use the appropriate command, usually /bin/zsh, to launch a new z shell process. Optional flags passed to the command control where the shell looks for new commands to interpret: