The 'Git for Windows' by default does not come with MSYS2 package manager called 'Pacman' and hence it is a limited version or subset of the MSYS2. Also the bash which supplied wih 'Git for Windows' is not a full version of bash hence does not provide for full Linux environment.
However you can get package manager support inside 'Git for Windows' in following ways :
- Install full MSYS2 and build Git for Windows yourself (Most git users don't require all packages and MSYS2)
- Install Git for Windows SDK (heavy & consumes around 3-5 Gb space)
- Use a hack to merge the MSYS2 Pacman packages with your existing Git for Windows installation