The format is:
<Target>[-Version]-<Src/Bin>-<Host>[-Cygwin Version]_<Date Code>[_personal tag].[extension]
<Target>

"mingw-w32" or "mingw-w64"
The target is the binary format the tool chain will generate.
"mingw-w64" means the toolchain will generate 64bit binaries that will run on windows natively (64bit windows required)
"mingw-w32" means the toolchain will generate 32bit binaries that will run on windows natively