My favorite thing about WinDbg is that many people pronounce it "Windbag".
So, no, WinDbg has nothing to do with debug.com.
I don't consider France to be part of the modern world, since I haven't visited Europe lately.
I say this as something who does all the things you described debug.com as doing, in this modern era.
Its assembler is sadly stuck in the pre-x86_64 era (and refuses to do arm at all), however it disassembles all of those fine.
Signed: someone who does pronounce it wind bag
edit: I see I simul-posted with u/modeless, but I can't remove it now that there's a (duplicate) reply. Maybe mods can remove or at least collapse mine (their ID is one lower so they were first)
So, no, WinDbg has nothing to do with debug.com.