Forgot this existed.
x86_64-w64-mingw32 is using the MinGW-w64 ABI created for MinGW-w64, a fork of MinGW. This is exactly the same AFAIK to
x86_64-pc-windows-gnu, just different terms from different timeframes. Honestly, GNU should catch up to modern naming, but at the same time, MinGW and MinGW-w64 came first, and
windows-gnu came later.
(w64 apparently is just something that can, probably, be swapped with
pcon those targets) I believe that, technically,
mingwABI on the
w64system, not the
mingwABI with a
w64vendor. Or at least, I'm guessing that's how the makers of MinGW-w64 intended it.