Comment 3 for bug 1271974

Yes, you need one file per .desktop file. At the moment there's no way of defining any kind of application dep chain, and I think from a end-user point of view it would be best if they could be installed/removed independently of each other. Of course, this is up to the distro packager. I don't know if it makes sense to show the viewers as independent "apps" in the software center or just the main calibre application. If you include all the .appdata.xml files upstream the distributor can then "cut up" the software into as many applications as desired, and also control which ones are shown in the software center.

All we're really asking for is more data. :)