Since version 5.3 @everydoor has become another editor that supports xmax:feature. In the picture is my first Christmas tree, which I mapped using it.

https://github.com/Zverik/every_door/releases/tag/v5.3

#OpenStreetMap

Same idea, but in the wild

But to be fair, half the tools in osm.ng are different (and not bad like React:), and osm.org handles heavy mapping queries through a module written in C++