Steps to Reproduce:
- Go to https://en.wiktionary.org/wiki/Special:UnconnectedPages
- Open the namespace dropdown
Only the Wikidata-enabled namespaces are listed.
There is a special item “all” on the top of the dropdown list to reset the namespace filtering, just like in Wikipedia.
This bug has probably connection with the fact that namespace 0 is not Wikidata-enabled on Wiktionaries.