I’d keep “JT Express” in old_name and any other defunct attributes you think are still relevant in disused:*=* tags.

I think it should be feasible for OHM to support more login providers besides OpenID. Feel free to file a request at https://github.com/OpenHistoricalMap/issues/issues .

JT Express used to have “Jimbo’s and Tengu Sushi” in their logo, in small type. Come to think of it, that would make it more of a strapline=*, since probably no one referred to it by that name. I’ve also added name:etymology=* per your suggestion.

There aren’t any hard-and-fast rules about how to name a chronology relation – it’s basically whatever you’d call the historical account if you were to write an article about it. So sometimes I go with the most recent name; other times the name by which it was best known.

Mergers and splits can get tricky. Since the JT Express relation also serves as a chronology for the pre-merger Jimbo’s, I’ve added that as an alt_name. In general, though, I’ve used a POI’s membership in two different chronology relations to indicate a merger.

There could be a chronology relation to track the occupants of a storefront over time. I haven’t gotten around to making them for most of the shops I’ve mapped, but I had a bit of fun with this one: https://www.openhistoricalmap.org/relation/2749168