355 Brake (pressure?) regulators - what are they doing?

Hey all, I'm in the midst of cleaning or replacing just about everything that brake fluid in the car touches, since mine was in such bad shape when I got it. Weak brakes due to gunk, cement-like deposits, slime, crystals, green stuff, etc. Anyway, I've got two parts for which I've ordered replacements, but I'm not at all sure what they are truly for. Maybe someone can enlighten me as to what exactly these parts do, and how?

First up, part #7 in this diagram is 154309 - Brake Pressure Regulator. Since it taps the line to the right front caliper, and isn't in a position to restrict anything, I don't understand how it can regulate brake pressure.

https://www.ferrariparts.co.uk/Diagram/Ferrari/F355-B-GTS-Spider-Mo-52---ABS-Bosch-F1/042-Abs-Bosch-Brake-System-Valid-For-Abs-Bosch-And-355-F1-Cars-

The other one is part #8 in this diagram, 172979 - Brake Regulator. Not brake "pressure" regulator, in spite of the fact that this one looks like it could conceivably do that, and despite the fact that there is plainly such a thing as a brake pressure regulator (see above). But just a vague "regulator." I think it goes to both back wheels. (I had to order this one from the UK, so I'll be using a cleaned-out old brake hose to replace it for garage and driveway use until it gets here.)

https://www.ferrariparts.co.uk/Diagram/Ferrari/F355-B-GTS-Spider-Mo-52---ABS-Bosch-F1/040-Hydraulic-System-For-Abs-Bosch-Valid-For-Abs-Bosch-And-355-F1-Cars-

So what are these things (supposed to be) doing? And how? Thanks in advance!

 

Thank you! Makes perfect sense.