[NTG-context] png and svg backend in mplib embedded in luatex

We are planning to drop the png and svg backend of mplib embedded in luatex . This means that if test.lua uses the png or svg backend $>luatex --luaonly test.lua will not work anymore as expected. To be clear:, *) metapost and mplib will stay as is now; *) mplib when embedded in luatex will loose the png and svg backend. ConTeXt doesn't use the png and svg backend, and it seems that LuaLateX doesn't use these backend too. So....does anybody use the png or svg backend of mplib embedded in luatex ? -- luigi