w:Template:Infobox_book/wikidata, wikidata:Wikidata-driven Wikimedia template, wikidata:User talk:ElanHR/Proposals/Schema for describing templates and their fields and Wikidata:Sister projects
Topic on User talk:Amire80/Flow
As you say there, the code has to be copied from one wiki to another. To resolve this, a common templates repository is needed.
The common repository is Wikidata. It must be taken as a task in Wikidata.
No, it isn't. It may be a repository for metadata about parameters, but not for the code of the template itself. It's not possible to transclude a template stored in Wikidata into the Spanish Wikipedia or into any other wiki.
So we need a CodeSister site to store the templates itself and take the metadata about parameters for TemplateData in Wikidata. It would be donde the first step: store medata parameters for TemplateData in Wikidata.