[Catalog-sig] How to get best match URL to find source?

[Tim Cera]

I am trying to get the best match URL that points to source.  How should 
I do that?

I can't use easy_install since as near as I can figure, I can't force it 
to collect only source.

I have tried something like below:

 pkgindex = PackageIndex()
 output = pkgindex.fetch_distribution(Requirement.parse(pkg), 'sandbox', 
force_scan=True, source=True)

It does download the package, but I can't find the URL anywhere.  Am I 
missing it?  Is it possible to get to?

Kindest regards,
Tim Cera