There are 11 questions using the-that, without tag wiki, including the following ones:
- When to use "That" instead of "The"?
- When can one omit "that" from a sentence?
- Comma after "that" midsentence?
While I could see a use for the tag in the first question, I think that using the-that to mean the question is about "the" or "that" is quite wrong.
For questions comparing the and that the tag could make sense, but I don't think there are enough questions to justify a specific tag when there are already less specific tags, but still specific enough to be used.
Do we really want to keep it?