The None category for maps is the default location plugin-wise for a map. The map location is mainly used for maps that are unfinished, for broken maps that needed to be removed from FFA (e.g. Miner's Millions, Magisterium: Ash, and Departure), or for lost maps that fall into the previous two categories. Board maps do not use the None category.
While maps in the None category have similarities to some sections of Mount Minr, maps typically need some form of submission to Board or Mount Minr itself to go in more specific categories, even The Canyon.