This screen allows to modify selected preferences sets, and to create or delete preferences sets.
When first using, a preferences set is created with a default name and default options. The toolbar + button add a preferences set initialized with default options, and with a default name. If you have several preferences sets, you may delete some.
A spinner allows to select a preferences set, display its content and change :
The screen bottom toolbar allows, for selected preferences set, to save changes, to cancel them, to reset to defaults (except name), and to delete it (after confirming).