Hi! As many of you know, a central global repository for Lua modules and templates has been a frequent request since the early days of the movement.

This year, I programmed a JavaScript tool called Synchronizer
https://www.mediawiki.org/wiki/Synchronizer

(inspired on a previous tool called DiBabel by User:Yurik)

The tool allows to synchronize (that is, automatically copy) Lua modules across Wikimedia wikis, and provides other features to help developers update and maintain global modules.

I also re-wrote the documentation at https://www.mediawiki.org/wiki/Multilingual_Templates_and_Modules to account for the new tool. It basically describes how to develop a Lua module that can be copied unchanged to any wiki, by abstracting things like user-readable strings and config.

Admittedly, this is a "poor man's version" of a proper solution to the problem, but one I find invaluable while developing and maintaining modules. Hopefully some of you may find it useful too!