Save, Save as, and POV gradient format You can also save a gradient in POV-ray format. Every edited system wide gradient will end up in your personal gradient directory. So if you want your system wide gradient back, just delete or move it from your personal directory. If you delete a system wide gradient, it just means that you don't want to use it in this session. But if you delete a personal gradient it will be gone forever.
Gradients can be very versatile.
You can use them in advanced fountain fills or patterns, but you can also create object-like things with them, like an eyeball, a hole or a pipe etc. You will just have to experiment and find out for yourself.