Download the package: http://www2.futureware.at/~nickoe/msys2-mirror/msys/x86_64/rsync-3.1.2-2-x86_64.pkg.tar.xz
Extract it and move rsync.exe
to %HOMEDRIVE%%HOMEPATH%\AppData\Local\Programs\Git\usr\bin
.
open windows cmd prompt.. maybe an admin one..
cd %TEMP%
curl http://www2.futureware.at/~nickoe/msys2-mirror/msys/x86_64/rsync-3.1.2-2-x86_64.pkg.tar.xz -o rsync.txz
tar -xvf rsync.txz
cp usr/bin/rsync.exe "%ProgramFiles%\Git\usr\bin"
I installed portableGit, added pacman and then used pacman to install rsync. By adding pacman, I could install more than just rsync.
I think the same thing could be done with Git for Windows. I just prefer to use software that doesn't need admin permissions if that flavor is available.