[Catalog-sig] simple index and urls exracted from metadata text fields

["Martin v. Löwis"]

>> Just make a specification. Notice that some links *already* have
>> a rel attribute which might be interesting to consider.
> 
> OK.
> 
> Any idea how we coud handle the dead links ?

IIUC, you don't have to follow them, right? If you want to download
the package, just follow the download links.

Regards,
Martin