By default, the path is C:\Program Files\Microsoft Visual Studio 14.0\SDK\Bootstrapper\Packages on a 32-bit system and C:\Program Files (x86)\Microsoft Visual Studio 14.0\SDK\Bootstrapper\Packages on a 64-bit system.
References :
https://msdn.microsoft.com/en-us/library/hh873130%28v=vs.140%29.aspx