Orion on iOS supports setting custom gestures on things like the location bar and toolbar (thank you for this! - they work well and are a big reason why I use Orion over Safari).
However, I feel that some of these gestures could be made more fluid. For instance, I use the swipe down gesture for closing tabs. It works as expected, but there is no feedback (either via animation or haptics) that I have started swiping and no indication that when I can stop swiping to execute the action. Also, the closing of the tab and being replaced with the next tab is somewhat abrupt. Video:
This is different from the swipe gesture that opens a new tab to the right of the current tab. When swiping left on the current tab, it moves towards the left of the screen and a new placeholder tab (with a "+") grows in size on the right. There is also haptic feedback to indicate that I can stop swiping. This is very well implemented - there is visual feedback on the progress of the action, haptic feedback to indicate to the user that they can stop, and the gesture overall is interruptible. Videos:
It would be fantastic if the other gestures can add also animations/haptic feedback! This is purely a cosmetic change so it's probably lower down the priority list but it would be great to be on the list nonetheless 🙂