The document /docs/DOC-23449 Increasing the Root Partition Size links to the Edison source files, but that page doesn't contain any source links for Edison.
An older version of the source(https://downloadcenter.intel.com/download/24271 Download Intel® Edison software package 1.0.3) also links to the "latest version" same as above.
I tried to find a way to comment on the page itself but there were no obvious button so I write the comment here.
The best download I've found is https://downloadcenter.intel.com/product/83268/Intel-Edison-Compute-Modules Drivers & Software or currently https://downloadcenter.intel.com/download/24910/Intel-Edison-Software-Release-2-1 Download Intel Edison Software Release 2.1
I suggest updating the links on the first document or better create a "Get the source" document and link to that.
Version, 3.0, can be found here:
Is there a difference between the "latest" 2.1 and the 3.0? Such as 3.0 being beta and 2.1 is stable?
You can see the updates this image has in https://software.intel.com/en-us/blogs/2016/03/30/intel-iot-developer-kit-30-release-notes IoT - Intel® IoT Developer Kit 3.0 Release Notes