These are standard, discounted economy tix. Not sure if this is the part in the rules that's relevant, but they state:

"OUBLE OPEN JAWS NOT PERMITTED.
ADD-ONS NOT PERMITTED.
END-ON-END
END-ON-END COMBINATIONS PERMITTED. VALIDATE ADJACENT
LINE OF FLIGHT FARE COMPONENTS ONLY. TRAVEL MUST BE VIA
THE POINT OF COMBINATION."