Please consider adding an option to back up manually modified about:config preferences as part of the Firefox Sync profile.
Many advanced users tweak these settings to improve performance, privacy, or compatibility. However, these changes are not currently synced across devices or restored after reinstalling the browser.
A monthly automatic snapshot, or manual export/import feature, would be very helpful for power users.
This would save time, reduce configuration errors, and make Firefox even more user-friendly for technical users.