If you're referring to the Msys64 based Win64 release it still exists on the website if you go to parent from the toolchain downloads and then into the releases directory. I figure the releases through Github actions are better anyway as the original MSys64 release was built with a now pretty old version of MSys64 and I wouldn't be surprised if it won't run properly with the run-time libraries provided by current versions of the environment now.
If you're referring to the Msys64 based Win64 release it still exists on the website if you go to parent from the toolchain downloads and then into the releases directory. I figure the releases through Github actions are better anyway as the original MSys64 release was built with a now pretty old version of MSys64 and I wouldn't be surprised if it won't run properly with the run-time libraries provided by current versions of the environment now.