Nimble is a simple mod that adds smooth transition animation on player perspective changes. It also makes screen rolls when you fly using elytra, and switches perspective when riding a vehicle.
The third-person front view now requires holding F4.
Client-side only. All these features can be disabled or configured if you have installed Kiwi. Besides, in-game config UI is provided if you have installed Cloth Config
Thanks to quat1024's Auto Third Person for the inspiration