The {{saved book}} template is required for saved collections to actually work, moreover the extension has features to edit its parameters, so the template should really bundled with the extension in the form of a parser function.

Not only this would enhance portability but also make updates easier, e.g. upon change of formats or deprecation of features.

Example of feature: letter-sized PDF. https://gerrit.wikimedia.org/r/165253

Example update: the removal of ODT and ZIM right now on Wikimedia projects. Editing the template on hundreds wikis is not nice, even though it "only" has some hundreds thousands transclusions across the cluster.

Example issue:

• http://web.archive.org/web/20110600000000/http://code.pediapress.com/wiki/ticket/804
  • Update book creator to handle new {{saved book}} parameters
  • Mostly about custom covers; T31849: Add metadata field in collections and saved books ? Continue there