the mod changes the fall damage calculation to use entity velocity instead of fall height, its been tuned to be close to vanilla with free fall, but will provide more realistic fall damage in falls influenced by something other than gravity, this mod also fixes an issue with fall damage, where the fall height would only reset if the player has any amount of upwards velocity, but this does not account for slow downs, so if the player fell 100 blocks, but somehow slowed down without moving upwards at all, theyd still take 100 blocks of fall damage even if they landed extremely slowly