Template:Shelf:Page?/doc

Usage
This template takes one unnamed parameter, and looks for a shelf with that name. Returns non-blank only if the shelf page exists and is apparently properly set up.

Internals
This template pings the shelf page, and checks for the correct response by Shelf:Page. The correct ping response cannot result if the shelf doesn't exist, and is wildly unlikely if the shelf page isn't properly set up. This template does not use the  magic word.