Base unit removal, unsure what to do about this block

[Chainsawcharlie]

Hi
I need to pull out a drawer base unit from my bathroom, not fitted by me.

I have removed most screws but I am faced with one of these in each top corner inside the unit, which I belive are called wall bracket hangers.

There is screw as pictured, then another single screw underneath.

The unit has a counter top above it.

What do I need to do with this screw please?
Am I right in thinking it will lift a latch to a rail behind the unit?
I cant see whats behind as the unit has a backing.

Many thanks

 

[ShaunCorbs]

Tbh you may need to remove the worktop or cut a hole in the back so you can lift the arm off the wall plate

 

[Chainsawcharlie]

Tbh you may need to remove the worktop or cut a hole in the back so you can lift the arm off the wall plate

Thanks Shannon, its next to a sink unit so hoping I don't need to remove worktop.
No problem to cut some of the back out.
Cheers for the reply