First ever white card shown in a football match: What does it mean?

The white card was initiated by Portugal to try and improve ethical value in the sport

Most football fans must be aware of the red and yellow cards in football. But history was scripted in Portugal on Sunday when a white card was shown for the first time in a women's cup quarter-final match between Benfica and Sporting Lisbon.

The match was going in favour of Benfica when the card was shown.

What does "white card" mean in sports?

The card was initiated by Portugal to try and improve ethical value in the sport. It is in contrast with yellow and red cards which are used to discipline players for misconduct. The exact purpose and consequence