Requests for comment/A central repository for templates and other bits and pieces

Background
Other MW wikis templates are either written from scratch or XML exported from Wikipedia.

Problem

 * Non-WMF wiki administrators are having to write and debug templates. This is an extra level in difficulty from just install MW, configure and then add extensions.
 * Upgrading MW to latest release, templates are not a trivial upgrade and otherwise might break.
 * Wikipedia specific features and images are sometimes included in other wikis.
 * Small or new wikis frequently don't have templates because they don't know it's a feature or find it difficult to implement.

Proposal
There should be a common repository for templates and other bits and pieces such as CSS and JavaScript.

How to implement?

 * What would this central repository need to work smoothly? Use a Git repository?
 * Not just templates, CSS, JavaScript and what else to include?
 * JavaScript gadgets, Scribunto modules, Lua modules, templates, CSS JavaScript, user pages ...


 * Where would this central repository be held, e.g. MediaWiki.org like for extensions?
 * MediaWiki.org is the documentation wiki for the MediaWiki software, not a repository.


 * Are these interwiki transcluded or installed like extensions and updated in sync with MW releases.
 * With interwiki transclusion there ought to also be a way to avoid name clashes.


 * Localisation of each template or module in many languages. Each debug needs to do the same in all languages. One solution could be to use exactly the same module in all wikis, but with a way to translate it with i18n tables, (this is the goal of the ControlArgs module).
 * Which templates to include, user selectable, handle interdependencies.
 * Licensing.