Thread:Project:Support desk/remove and from extension name/reply (3)

Not the alias file, the languages ;)

Look at: https://www.mediawiki.org/wiki/Manual:Special_pages#The_Messages.2FInternationalization_File

The title of the Special Page comes from the message file, in your case from key "AddAds". If the key doesn't exist (like in your case), the message key will be shown with <>.