Anti walk pins needed when using Timney triggers? : r/MPX

Dumb question, but what is this part on these MPX i see everywhere?

Rise Armament RA-434 High-Performance Trigger (Options)

Sig MPX with binary and anti walk pins? : r/MPX

SIG MPX PCC Anti Rotating Pin - Pistol Caliber Carbine - Brian Enos's Forums Maku mozo!

Dumb question, but what is this part on these MPX i see everywhere?

Anti walk pin recommendations please.

Firearms - WTS-Loaded MPX

AR15 anti-walk pin set for AR-15 lower receivers

SIG SAUER MPX Trigger - Timney Triggers