Since Chromium and Firefox (and soon Firefox for Android) all have different availability of settings, information about the browser and OS type should be stored in the backup JSON files. When a user tries to restore a backup, they should be warned if the backup file is from a different platform. They can still bypass the warning to import the file.
If there is no platform information saved in the backup file (as would be the case for legacy backup files), don't show a warning to the user.
Since Chromium and Firefox (and soon Firefox for Android) all have different availability of settings, information about the browser and OS type should be stored in the backup JSON files. When a user tries to restore a backup, they should be warned if the backup file is from a different platform. They can still bypass the warning to import the file.
If there is no platform information saved in the backup file (as would be the case for legacy backup files), don't show a warning to the user.