When a user visits a Norwegian-Bokmål article, a meaning-less generic "Norwegian" interlanguage red link is shown. The link leads the user to create a new Norwegian-Bokmål article which already exists. The generic "Norwegian" should not be considered on the interlanguage links, only specific versions of Norwegian (for which Wikipedias exists: Norwegian-Bokmål and Norwegian-Nynorsk) should be considered when showing red interlanguage links (if CX is enabled for them, and the article is really missing!).
Norwegian language appears as a target language in the Norwegian Wikipedia if no or nb are accept languages. This is because "no" is the language in the domain and "nb" is the content language.
It probably makes sense to make a function in the ULS extension that returns a list of Accept-Languages normalized for MediaWiki-based sites.
This may affect other languages for which Wikimedia uses not-entirely-orthodox codes.
"Unbreak now" because it affects display of usual articles in production for people who enabled the beta feature.