Shooter Game Sample. What is MyPawn ? How is it declared

I have been walking through the shooter game inside and out and I can not find for the life of me where that stupid variable is declared. Can someone explain how AShooterCharacter magically is defined in the variable MyPawn ???

Thanks in advance

The only times I see MyPawn it is either declared in the header e.g. (ShooterWeapon.h:263)
/** pawn owner /
UPROPERTY(Transient, ReplicatedUsing=OnRep_MyPawn)
class AShooterCharacter
MyPawn;

or casted from the current pawn e.g. (ShooterHUD.cpp:135)
AShooterCharacter* MyPawn = CastChecked(GetOwningPawn());