Was soll diese Erweiterung leisten? Wo ist der Vorteil? Nativ bildet doch das Mediawiki eine Klasse für den jeweiligen Namespace. Werden hier die Erweiterungen als separat ausgelagert, wie in anderen Erweiterungen dieser Art? Ich mein ist spannend und war ganz sicher Arbeit, aber ich verstehe den Mehrwert gerade nicht, vielleicht übersehe ich etwas wesentliches.
// I don't get it, what's the benefit of this extension? write an additional file instead using the classes like .ns-3000 ?
This extension is meant to help wiki admins add styles to individual namespaces that are loaded only in that namespace. If you have a lot of namespaces (let's say for different departments in an enterprise wiki), it simply gives you an option to maintain the individual namespace style sheets separately and see directly in the GUI which namespaces use their own style sheets and which don't. Therefore, you don't need to load all these styles in common.css (which can get pretty convoluted at times) or change server settings to accommodate additional namespace-specific style sheets if you want to separate them out.
It's simply a convenience feature, but does not add any additional functionality. It was created specifically for a BlueSpice environment and, you are right, can easily be "skipped" for standard MediaWiki installations.