where are edison and due source files after installation using boards manager

I installed the support for Due and Edison from boards manager but I cant find any source files related to these two in the arduino tree.I am using arduino 1.6.4. Could some one help me here.I want to dig into the source change some things like clock, clock for SPi etc.

I suppose you are using windows: then it's %APPDATA%\Arduino15\packages

Yea got it .Thanks!