component ID in this design?

[Drake]

This is a hydronic control design that I might like to use for my new project but there are a couple of components that I do not know what they are or can fully see how they are plumbed. If anyone can help it would be appreciated.

My hydronic plan is a single zone, single temp main floor in slab pex design but have a second floor(open to first) sleeping area. I believe enough heat will naturally rise to keep in warm(R 90 ceilings) but as it has thin slab passive storage floor I will be installing a single pex loop just in case. So the second zone design shown would be easy to add with this design if plumbed(and capped off) for if needed.

It's not quite visible but doe the hot line to the single loop second zone run behind pump and connect to to first zone hot line below pump? The line with the actuator valve?

I do not know what the larger silver box on the far left is/does for sure or the two white boxes above it. They must be to thermally control the zones in some way. Thank you for any input.

I do not see a sediment trap but would add one in the lower common return cppr run.