I’ve just opened the OSM site on my PC to have a look at the history in my area, and I’ve seen this apparently massive edit. It covers most of the US, a lot of Canada, and a significant chunk of Europe and the UK.
wheelmap_visitor says that ‘This is a proxy user for all wheelchair tag changes happening on Wheelmap by anonymous users of the website and app Wheelmap.org.’ so does this mean that if someone has made edits to areas inside the rectangle at some point recently that they all get included in this edit?
This is a longstanding issue that wheelmap knew and promised to solve.
Some info from the OSM talk mailing list.