Shopping for flights to SFO this morning, I came upon this strange fare code. Clicking on fare rules gives me a "no fare rule found" error. And my search function is not cooperating this morning. I did apply an Entertainment book coupon to the fare, could that be it? The PDX-SFO is a VA21DNX fare.

United Airlines 1170
Airbus A320
Jul XX 8:10 pm depart SFO
Jul XX 9:47 pm arrive PDX
stops: Non-stop
Class: Coach
Fare Basis Code: UA
Booking Class: U
Fare Rules