What is this part?

[alwaysFlOoReD]

so the reservoir doesn't have the two seperate fluid spots inside? at the top, they share fluid but as the fluid leaks down, at a certain point there is a front reservoir and a rear reservoir? i though all vehicles had that set up and that was how the front/rear systems worked since the plunger pushed past the orifices for both as you push the pedal?

That's what I think as well.