It is waxed plaster, at least what I have in mind is. It doesn't look
like faux anything, it's just a plain coloured wall where the wax gives
it a smoothness and texture. The idea is that the plaster is tinted in
the desired colour, applied to the wall very smoothly, and then the wax
applied to that.

This website mentions a stylish modern home where the technique was
used, but unfortunately doesn't show photos:
"https://www.baltimorestyle.com/so01issue/city-so01.html".