I don’t understand what the timers labeled “still yours” mean in the sample images. Is that just a user label or some sort of special category for eg uncategorized time?

I also don’t understand what the different colored parts of the ring represent.

Thank you for your questions!

"Still yours" shows the total time available over all priorities.

The different ring segments represent the time allocated (available=light and used=dark) of each priority in the color you assigned to that priorty.