I think it makes sense to split the tag. The new tags should be intuitive to users, and have a clear explanation of their intended usage in their wikis. Here's my suggestions:
emacs-history :: use this tag for questions about the history of emacs. i.e., the development of the Emacs program, or people associated with it over the course of its development
input-history :: use this tag for questions about using, storing or otherwise manipulating the history of user inputs. e.g., search history, command history. Don't use it for the
kill-ring, which has its own tag
file-history :: use this tag for questions about storing previous versions of a file, or locations within that file.
file-history in this schema seems like it might be a synonym for something else, maybe something related to version control?