Template:Shelf:Allbooks category?/doc

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

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