I tried to search cs:Category:Údržba:Wikidata only in talkpages (I was discussing this category some years ago). I selected only talk namespaces. But there was 125 results, all in namespace 14, which was not selected.
Topic on Help talk:Extension:AdvancedSearch
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And second "bug" - search URL is not easily copyable to wikitext
Hi @JAn Dudík, thanks for the report! I created a ticket for the bug: phab:T195832 and we will look into it. I also created a ticket for the second issue, so that we have it on our radar - phab:T195833.