The biblical text places Mount Hor in an itinerary rather than at a location, on the border of Edom between camps that are themselves unidentified. The traditional identification with Jebel Harun above Petra is comparatively late and rests on the tradition itself. A competing identification places the mountain considerably further north, nearer the edge of the Negev, on a different reading of the route.
What would resolve this Excavation or survey producing an independent identification of any camp on the wilderness itinerary, or an early inscription or cultic deposit on either candidate summit that ties it to Aaron independently of the later shrine tradition. Failing that, the question stays open and the atlas records the identification as traditional.
OpenBiblical archaeology and historical geography of the southern LevantDivinity Atlas Open Questions Register, First Edition