Split Circuit Outlet

In the above picture there are two separate ungrounded conductors (hot) on a dual breaker coming to the outlet, ( the black and red wires), the single grounded conductor (neutral) gets connected at the panel to the neutral bus, there is also a equipment grounding conductor (bare wire) that gets connected to a grounding bus at the panel and to the outlet electrical box (if metallic) and to the grounding screw of outlet as well as any onward cables.

A split circuit is connected to a dual breaker at the panel, it is bridged so that is one circuit trips both circuits trip, at the outlet (or outlets) the joining tab between the brass color screws is broke off and the top half and bottom half of the outlet is on a separate circuit however a single grounded conductor (neutral) is used for the return. The two ungrounded conductors (hot) from separate circuits is connected to the brass color screws of outlet. Recent code revisions are now requiring circuits over the counter top near the sink to also have GFCI protection. Now that creates a problem with split circuits that to date I have never seen a split circuit GFI outlet. I have also read that there some variations on the type of outlet including some stating that the NEC allows to pass through 20 amps on a 15 amp outlet. Personally I prefer never to have anything that has been rated for 15 amps carry 20 amps.