This message was posted on behalf of Intel Corporation
The libraries available for the Galileo Board are located in the location: C:\Users\”Youruser”\AppData\Local\Arduino15\packages\Intel\hardware\i586\1.6.2+1.0\libraries
The libraries for Mouse are not available for Galileo, as you know the Arduino IDE works for all the Arduino boards too so that is the reason why it comes included in the IDE. If you want to use the Arduino IDE with your Galileo Board, take a look at the available libraries.
I suggest you to always use the latest Arduino IDE version in order to have the latest updates in it.