The --urls option is not what I mean... it shows where a package is available 
*now*. Note if you 'smart channel --disable cooker', the 'Cooker' channel is 
not shown anymore in the Channels: field for a package. 
 
What I mean is for Smart to record the repository and URL from where the 
package was actually downloaded/installed, possibly never losing nor allowing 
changes to this information, except automatically deleting it when the package 
is removed. Note the "origin" information would stay even if the origin 
channel was removed.