What component divides the left manifold from the right manifold?

The component that divides the left manifold from the right manifold is indeed the XBLEED valve. This valve serves a critical function in the aircraft's pneumatic system. It allows for the isolation of the left and right air supply systems, ensuring that the two sides can operate independently when needed.

When the XBLEED valve is fully closed, it prevents any bleed air from the left manifold from affecting the right manifold and vice versa. This separation helps maintain optimal system performance and can be crucial in certain operational scenarios, such as during system failures or to balance environmental controls on each side of the aircraft.

The other components mentioned do have important roles within the aircraft's systems but do not serve the specific purpose of dividing the two manifolds. Understanding the function of the XBLEED valve helps in grasping the broader context of pneumatic system management in aviation.