What are the QO breakers that have a weird stab on the back that looks like a fork?

Product Line:
QO Miniature Circuit Breakers

Environment:
QO Residential Load Centers and Breakers

Resolution:
They are the old Class NI QO circuit breakers. A cutout from the old digest below shows the purpose of these breakers and pictures. They can be replaced with the current standard QO circuit breakers.

Released for: Schneider Electric Canada