AppStream warns on insecure URLs
See: https://appstream.debian.org/sid/main/issues/gnome-subtitles.html
Hints asv-screenshot-media-url-insecure org.gnome.GnomeSubtitles.appdata.xml:78 - http://gnome-subtitles.sourceforge.net/files/screenshots/Screenshot-GnomeSubtitles-VideoTimesTranslation.png Consider using a secure (HTTPS) URL to reference this screenshot image or video. asv-screenshot-media-url-insecure org.gnome.GnomeSubtitles.appdata.xml:84 - http://gnome-subtitles.sourceforge.net/files/screenshots/Screenshot-GnomeSubtitles-SynchronizeTimings.png Consider using a secure (HTTPS) URL to reference this screenshot image or video. asv-url-not-secure org.gnome.GnomeSubtitles.appdata.xml:75 - http://www.gnomesubtitles.org/donate Consider using a secure (HTTPS) URL for this web link. asv-url-not-secure org.gnome.GnomeSubtitles.appdata.xml:73 - http://gnomesubtitles.org Consider using a secure (HTTPS) URL for this web link. asv-screenshot-media-url-insecure org.gnome.GnomeSubtitles.appdata.xml:81 - http://gnome-subtitles.sourceforge.net/files/screenshots/Screenshot-GnomeSubtitles-VideoFrames.png Consider using a secure (HTTPS) URL to reference this screenshot image or video.