Presuming its 2/23, nothing below full Y on that flight:
F7 D7 P6 U0 A0 Y7 Z7 S0 B0 M0 H0 Q0L0 V0 K0 G0 T0 R0 X7 N0 W0 E0
ETA: I see X7 is also open. So you can buy “Saver” on an underlying refundable fare but all of the Saver restrictions then? At least it should still be eligible for CoS bonus...