What does a yellow card indicate?

A yellow card serves as an official caution to a player for committing a foul or engaging in unsporting behavior. It is an indication that the player's actions have violated the rules of the game, and the card serves to formally document the infraction. If a player receives a second yellow card in the same match, it results in a red card, leading to ejection from the game. However, a single yellow card is not a punishment of expulsion; rather, it is a warning and a way to maintain discipline on the field. Understanding this function is crucial for managing player behavior and ensuring fair play in matches.