In the other direction from tag merging there are occasionally single tags that should be split, or at least clarified what they actually mean and some posts retagged. In particular, the tag limits seems to be unclear about whether it refers to limits in analysis or in category theory. I think it makes more sense for it to refer to limits in analysis, with the couple of category-theory questions currently having that tag being retagged as ct.category-theory (except the one question about the relationship between the two), but I'm not sure whether the tag "limits" could be renamed or "annotated" somehow to make clear that this is what is meant for future use.