I headed towards the download section for the EMF Compare component and downloaded the official 2.1.0 release (yay, congratulations!). We usually maintain the sources for all the bundles in our product's target platform. However, the 2.1.0 release misses the *.source.jar files for certain bundles:
I may have missed some plugins when setting up the build for source generation. I'll look into it asap (for now, your best bet is probably to retrieve the sources from git).