Recently, there was some confusion as to why a single-use tag without a tag wiki wasn't auto-burninated after six months. It was later discovered that as someone made a rejected proposal for the tag wiki, a blank wiki was automatically created by the Community user immediately upon edit submissio...

From what I understood about tag pruning, tags which are used only on one question are automatically removed if they are used only on one question. This happens after the tag is 6 months old (if it did not attract other questions in that period). The exception is that tags which have a tag-wiki a...

So this is interesting. Technically speaking, that tag does have a wiki. It's just blank. The wiki's post ID is assigned to the tag, and you can view the revision history showing it was created shortly after the post was created: https://mathoverflow.net/posts/295234/revisions Having the wiki cr...