Cloud providers file in datadir is not flatpak compatible
I just tried to do a nightly flatpak build of the Nextcloud client that has support for libcloudproviders. Unfortunately the the ini file, required for the client to be recognized by libcloudproviders is not exported by flatpak.
According to https://github.com/flathub/org.filezillaproject.Filezilla/pull/1#issuecomment-354509330 flatpak only has a limited set of export types.
We could add the support for those files to flatpak (as it is also done for the GNOME search providers for example).
Another option would be to use the Implements key in regular desktop files to hint that an application implements the org.freedesktop.CloudProviders.Provider interface. That solution cloud be added to libcloudproviders by parsing desktop files for that key in addition to the existing ini files.
See https://standards.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#interfaces for the Implements keyword.
@csoriano I'd like to hear your feedback on the two ideas. Not sure which is better at the moment.