When I build my product .eclipseproduct is generated. Is this file still relevant for Eclipse 3.6+? Is there a way to modify this file to reflect my product? I know I can alter this file myself, but was wondering if there is a plugin that can do this?
In the installation profile (p2/org.eclipse.equinox.p2.engine/profileRegistry/<ProfileName>.profile/<highest number>.profile.gz) of your product installation, you can find out where the .eclipseproduct file comes from: It is extracted from the artifact org.eclipse.rcp_root. That artifact will always be installed when the org.eclipse.rcp feature (p2 id org.eclipse.rcp.feature.group) is installed.
So this file is not generated by the build, but it comes with artifacts referenced in your build. If you want to learn about it's purpose or want it to be changed, you should contact the providers of the org.eclipse.rcp feature.