Despite the importance of on-wiki code (gadgets, site scripts and user scripts) to our projects, there are no guidelines on how to write code in skins, extensions in a way that supports these users.
The lack of guidelines historically has created unnecessary conflict between editors and Wikimedia developers. For example, the common task of changing a class name can cause havoc with certain gadgets that depend on associated styles.
I have spoken to various developers across MediaWiki extensions and it seems pretty clear to me that a policy would be helpful for establishing expected norms.
I've begun drafting a policy based on the discussions I've been having with Wikimedia engineers on: