When a goalkeeper is in control of the ball with their hand(s)/arm(s), the referee raises one hand and uses their fingers to signal the last five seconds of the eight-second time limit, often moving their arm up and down as they do so. The countdown from five to zero:
 helps the goalkeeper avoid conceding a corner kick for exceeding the eight-second limit
 signals to the goalkeeper’s team-mates to get into position to receive the ball before the countdown ends

IMPORTANT

 If the goalkeeper is starting to kick/throw the ball as the countdown reaches ‘zero’, this is within the ‘spirit’/’intention’ of the Law, so the referee should allow play to continue.

 The referee’s signal is intended to assist the goalkeeper with complying with the Law, but the absence of a signal does NOT mean the goalkeeper can hold the ball longer than eight seconds/avoid punishment.