Firefox automatic backup that can be configured in Settings / Account and sync is a great feature I have just found recently.
But I don't want to keep a copy of the backup file permanently on my disk. I would like to create it just before I do my periodic backups to an external storage.
I propose to add a command line option to FF with which it could create (in a headless mode) the exact same backup file as created by the mentioned feature, so FF could be employed in a backup script.
Backing up the entire profile is not a good alternative: even after filtering and compressing my profile data, it is today 50 MB, while the FF automatic backup file is less then 25 MB after compression. On top of that, I am not 100 % sure that my filtering discards only irrelevant data, while it is rightful to expect from the internal FF algorithms to do an exact separation of relevant / irrelevant data.