If you try to import a dump with (for example) Scribunto modules into a wiki that does not have Scribunto installed, you get "No handler for model 'Scribunto'' registered in $wgContentHandlers", followed by a big scary stack trace. We should catch that and emit something more useful, like a hint to go look for an appropriate extension.
Maybe we should create a MediaWiki.org mapping of ContentHandler types to their canonical implementation..
Version: 1.22.0
Severity: minor