I'm looking at the stock late top mounted fuel pump. It has a metal canister around it and around the fuel pump.

It is not a sump for the pump.
It is sealed off from fuel all around except at the top.
The fuel pump would not be surrounded by fuel for cooling.

Is it for baffling to keep the pump from being 'bashed' by fluid waves?
It it just for 'scaffolding' to hold everything in place?
Can it be perforated and still work?
Can it be removed completely and still work?

 

I took it all apart. Took the top off, now I can see what it does.
Just as I thought, the FPR return just dumps out the top and catches in the canister.
This is because there can be air and turbulence in this return fuel to the tank.
The canister seems to buffer the return fuel.

 

Thank you. I dropped my tank last week and was wondering what that was myself!