We have lot of documentation starting from https://www.mediawiki.org/wiki/ResourceLoader
One thing which is lacking, would be a step by step tutorial to build an extension from scratch that will just load a css and a js.
Version: unspecified
Severity: enhancement
I'm not sure it is really lacking.
These two are both pretty well documented. ResourceLoader takes a lot of maintenance and set-up steps out of the developers hands.
Especially for a new extension all it is is this:
Both of which are described on on mediawiki.org. Just now I've rephrased some of that and moved it here: [[mw:ResourceLoader/Developing_with_ResourceLoader]] (#Registering and #Loading_module respectively).
The other things (debugging features, special CSS anotations etc.) are optional, and were already documented under /Features and Developing_with_ResourceLoader.
We definitely have a lot of documentation about RL. What this bug is about is really writing an introduction to the resource loader for newcomers / newbies. We have recurring requests on MediaWiki-General about how to add a JavaScript file to an extension, I usually end up pointing people to the WikiLove extension as an example. A tutorial would let them start up their extension more easily.
See also bug 37805 which is about writing an example extension in mediawiki/extensions/examples