How to Add rsync to Git Bash for Windows 10
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
The "(extract 4 libs to folder "usr")" part confused me. Each of these packages contains their own /usr/ directory tree (in particular /usr/lib, /usr/bin). Just extract all these /usr/* to a new "usr" folder and then copy it to "C:\Program Files\Git". It works, thank you!