Sometimes when messing locally with different things, a page might look broken.
Then I look at the response for a request like:
And it's near impossible to figure out that something is wrong. In this case, module "mediawiki.skinning.interface" could not be found.
debug=true makes no difference in this regard.
Had it been a regular request that isn't only=styles, it would've contained :
We should probably treat this the same as we do in case of exceptions and other errors in stylesheet requests, namely by prepending a comment to the response body.