Currently Commons content is being used, without any filtering, in the Search Preview. Files nominated for deletion will be downranked (articles with “Template:Deletion_template_tag” get a negative boost) compared to others, but they may still show up.

Requirements:
Implement a filter so that Commons files that are nominated for deletions don't appear in search preview.

Implementation note from Matthias: use hastemplate:Deletion_template_tag in the search for those files