What is React component 'displayName' is used for?

Question

I know that is it considered a good practice to name react component by adding a displayName property, but not sure I know why. In react docs, it say:

Answer 1

this article helped me:

How do I get string name of React Native component class?

    class CardGroup extends Component {
      render() {
        return (
          
{this.props.children}
        )
      }
    }
    CardGroup.propTypes = {
      children: function (props, propName, componentName) {
        const prop = props[propName]

        let error = null
        React.Children.forEach(prop, function (child) {
          if (child.type !== Card) {
            error = new Error('`' + componentName + '` children should be of type `Card`.');
          }
        })
        return error
      }
    }