## The current behavior

The full value of the `key` is very difficult / impossible to find and use in the interface of the React Devtools.

![Kapture 2020-04-22 at 11 47 47](https://user-images.githubusercontent.com/1935696/79997715-25222680-84ba-11ea-97ba-51f1679a8c91.gif)

Only managed to find it by accident :(

## The expected behavior

The `key` is visible in the props list to the right.

### Detailed Proposal

As mentioned below in https://github.com/facebook/react/issues/18702#issuecomment-617924196

Add a light divider and new section in the props panel to the right.

Potentially also add a question mark that shows an explanation about the fact that things in this section are not really props.

Ref (Original implementation): https://github.com/facebook/react-devtools/pull/328
const name = getDisplayNameForRoot(fiber);
    const counter = rootDisplayNameCounter.get(name) || 0;
    rootDisplayNameCounter.set(name, counter + 1);
    const pseudoKey = `${name}:${counter}`;
    rootPseudoKeys.set(id, pseudoKey);
  }
  function removeRootPseudoKey(id: number) {
    const pseudoKey = rootPseudoKeys.get(id);
    if (pseudoKey === undefined) {
      throw new Error('Expected root pseudo key to be known.');
    }
    const name = pseudoKey.substring(0, pseudoKey.lastIndexOf(':'));
    const counter = rootDisplayNameCounter.get(name);
    if (counter === undefined) {
      throw new Error('Expected counter to be known.');
    }
    if (counter > 1) {
      rootDisplayNameCounter.set(name, counter - 1);
    } else {
      rootDisplayNameCounter.delete(name);
    }
    rootPseudoKeys.delete(id);
  }
  function getDisplayNameForRoot(fiber: Fiber): string {