Bug 690257

We deliberately do that, so that the user gets a "You can't do that Dave" message, rather than a file extension know known dialog.

If you think it's saner to just not handle the x-deb type then your fix makes sense.

Created attachment 487400 [details]
Failure dialog

That makes sense, but the dialog displayed in my opinion is actually worse than a "file extension not known", see attachment (current F-14 x86_64).  It says "The file is not valid" which makes no sense to me in the first place (something like "This package format is not supported on this system" would be better), and "MIME type not supported ..." in the details which kind of begs the question why did the package installer register to handle that particular MIME type, then?

BTW if gpk did not register to handle these files, they would be opened with File Roller at least in my GNOME setup, so there would be no "unknown file type" or the like messages.

As it stands now, I think it would be better to remove association with MIME types that are known to not work on a Fedora system.  But if the dialog would be improved and offered a fallback option for opening with File Roller, then it'd be the best of both worlds I think.  For example something like this:

+------------------------------------------------------------------------+
| Failed to install file                                                 |
|                                                                        |
| This package format is not supported on this system.                   |
|                                                                        |
| More details                                                           |
| Packages of type application/x-deb (Debian package) are usually meant  |
| for Debian and Ubuntu systems and are not installable on this system.  |
| The package formats supported on this system are: [...]                |
| You can use Archive Manager to browse the contents of the package.     |
|                                                                        |
|                         [Open with Archive Manager]  [Close]           |
+------------------------------------------------------------------------+

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