As hopefully most of you have heard, I'm working on changing the system we use to configure Wikimedia production. The main purpose is to make it output static files and reduce the amount of "code" executed on each page request as much as possible. This means that much of the way that people on this list write and deploy configuration patches will have to change.

You can read some details at T223602, but the short version is that there'll be a YAML file for each wiki which will set unique configuration for that wiki, and a set of YAML files for "traits" that wikis can inherit from (e.g. in this demo change for bnwiki, I'm making it inherit a set of configuration for the "mobilemainpagelegacy" trait). There won't be an InitialiseSettings file or feature dblists any more. Much of the configuration in CommonSettings.php will be moved into these files too. Changes to configuration YAML files will be "compiled" into a static JSON file per wiki (example for bnwiki) at merge time.

I'd really appreciate thoughts/ideas/concerns/questions any of you might have.