Igor - that block is the original license of xulrunner; we can't change that. It just means its triple licensed under MPL and GPL/LGPL.
If we removed it we would be breaking the license.
About creating a page for the license descriptions...the About box in Eclipse aren't enough ? (that one is at least uptodate ;)
If you could make something that generates such a page based on an eclipse installaiton (i.e. p2 repository) then sure, we could make that
part of the build to generate a "license-overview" html page.