@GrayFace The original question implies that OP already has MSYS2 installed, the other answer assumes that too. "packman returns 404" If this is an old MSYS2 installation, you should try reinstalling. Otherwise you should point it to a different mirror. ".zst can't be opened with anything I have" It's a zstd archive. Quick googling points to this: github.com/mcmilk/7-Zip-zstd Or use
tar -xf (which needs zstd.exe to be installed).