berkeley-hardfloat | repository contains hardware floating-point units | Apps library

There are brief definitions of Queue and other Standard Library Interfaces of Chisel (Decoupled, Valid, etc) in the Cheat-Sheet and a bit more detail in the Chisel Manual. I also found these two answers here at StackOverflow - here and here.

However, neither of these resources explains in the plastic way - and I feel that would help me better understand the purpose of these Interfaces - what do these lines of code synthesize to - what do they look like in actual hardware?

For example, here is a snippet of the FPU code from the package HardFloat:

val input = Decoupled(new DivRecFN_io(expWidth, sigWidth)).flip

where DivRecFN_io is a class as follows:

class DivRecFN_io(expWidth: Int, sigWidth: Int) extends Bundle { val a = ... val b = ... val ... ... }

What exactly is achieved with the line containing Decouple?

Thank you.