## 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
let displayName = getDisplayNameForFiber(fiber);
    const index = fiber.index;
    switch (fiber.tag) {
      case HostRoot:
         R
         I
        const id = getFiberID(getPrimaryFiber(fiber));
        const pseudoKey = rootPseudoKeys.get(id);
        if (pseudoKey === undefined) {
          throw new Error('Expected mounted root to have known pseudo key.');
        }
        displayName = pseudoKey;
        break;
      case HostComponent:
        displayName = fiber.type;
        break;
      default:
        break;
    }
    return {
      displayName,
      key,
      index,
    };
  }
   Produces a serializable representation that does a best effort
   of identifying a particular Fiber between page reloads.
   The return path will contain Fibers that are "invisible" to the store
   because their keys and indexes are important to restoring the selection.
  function getPathForElement(id: number): Array<PathFrame> | null {