The ability to show the phrase varnames in the ACP and Modcp. This works on all phrases, with the exception of, settings phrases. The way vBulletin shows them is different from any other phrases.
It is possible to show them with a file edit, which we don't like to suggest but it is the only way to do so. The instructions for the file edit can be found in the readme.txt file in the zip, and on the settings page for the mod.