The heuristic tag has only one question, no description, no synonyms and no wiki entry. The only question using it has four other tags and a comment pointing out that the use of the word "heuristic" (which appears in the title) is ill-chosen in the context of this question. Seems like a good candidate for elimination.
One-off tags are automatically deleted after six months, according to the answer I got here on Meta Stack Exchange. So unless somebody else uses the tag meanwhile, there's no need to take action.