Turtlebot 3 Localization: IMU for Odometry? Is Odometry the only localization component?

Hey all. I am trying to understand the localization part of Turtlebot 3 Burger.
From what I understand from turtlebot3_core, by using an IMU to calculate rotational values from the wheels and translating them into odometry and updating it in the world_map.

Please kindly correct me if I am wrong and aside from odometry, may I know if the LIDAR plays a part in Localization?

Regards,
Bobby