Would be good to have here a search field for MD5 sum, as other fields are less comfortable to guess is some module exists here already. With current fields you may get several results, and then you need manually check them or do another search.
Also, sometimes I saw as current fields did not find what they should (din't remember concrete situations, but there were several). Hence, you generally need to make search by several fields to be sure in module's absence.
When it's needed. You want to rate or comment some module. Or you choose modules for uploading: on 1st step you do a preliminary sorting with checking wich modules absent here, on 2nd step you make final choose.
The site keeps MD5 checksums and checks them during uploading. It should be easy to implement in modules searching form.