The 20-minute red card is the new rugby law that has been introduced for the Autumn Internationals but what is it?

Referee Wayne Barnes of shows a red card to New Zealand captain Sam Kane during the Rugby World Cup 2023 Final
Referee Wayne Barnes of shows a red card to New Zealand captain Sam Kane during the Rugby World Cup 2023 Final (Photo by Tom Jenkins/Getty Images)
The 20-minute red card is the new rugby law that has been introduced for the Autumn Internationals but what is it?