I have running liferea for a couple of months in confined mode (I am the official package maintainer) . All of it works, except for downloading content or opening media files. Liferea lets users choose the app to download podcasts. I know liferea should use xdg-open to open files, but for downloading content? Also, mainstream should remove a lot of the interface of liferea. Also, I think there is no standar way to request to download files (except for using a browser)
This is the config dialog with the download/open options.
In the combo are available Transmission, kget, gwget, steadyflow and “custom”. Also, you can configure an opening app per type. I think I can add wget, and configure it by default (maybe). For the opening part, I can use xdg-open, but the GUI will be useless. The other option (I already did this) is tell the author to modify liferea to use standard methods to download or open files, but in the stable release this feature will be not available in the near future.
I am not a gnome developer so I do not understand enough to create a patch (I haven’t developed in C for a while). So, for now Liferea works, but that gui is useless and liferea can not download content
This to me suggests that the liferea snap should ship all the backends it intends to use. Classic is not typically granted for access to arbitrary files. Besides, snaps can be installed on many different versions of many different distros so for your snap to work robustly everywhere, it should ship everything it needs (you can use stage-packages or stage-snaps for that).