This card tracks a top 10 wish from the Community Wishlist Survey: https://meta.wikimedia.org/wiki/2015_Community_Wishlist_Survey
Original proposal: We could use a single location where to keep templates, Lua modules, and Gadgets that are used on all the wikipedia projects. Just like images from commons can be used on other projects, code from such site would be visible to all the projects. The current system of 100's of out of sync copies of the same templates or Lua modules occasionally synchronized with the original is very hard to maintain. --@Jarekt (talk) 20:06, 10 November 2015 (UTC)
Community Tech preliminary analysis:
Support: High. Strong support, but there are some important concerns expressed in the voting about the difficulty of using templates across wikis. Templates are already complicated, and this project could be offering a technical solution to a problem that needs social, consensus-based solutions.
Impact: High. Existing templates, gadgets and modules (across all wikis) will probably be affected.
Feasibility: Difficult. We're currently working (mid-January) on getting the Gadgets 2.0 Gadget Manager ready for review (see T31398). That doesn't include global gadgets, but it's a step in that direction. Creating a global repository will depend on using shadow namespaces -- there's currently an RfC about shadow namespaces on mediawiki.org. There are also notes and discussions from the Developer Summit in early January here: T115762.
Risk: High. Templates, gadgets, and modules are implemented differently and may need different solutions. Templates often transclude other templates. Adding translation support to templates will make them harder to maintain. We'll need to figure out how permissions will work, and how template and module editors can test on multiple wikis or provide a warning of changes. We need to also think about Gerrit-like code review needs for templates, gadgets and modules and possibly even a versioning system. It will be difficult to come up with a solution that will truly work across projects and will fit into the social structures of diverse communities.
Status: This work will probably depend on the shadow namespaces work, which is still being discussed, and probably won't be complete by the end of this year.