## 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
return alternate;
    }
    primaryFibers.add(fiber);
    return fiber;
  }
  const fiberToIDMap: Map<Fiber, number> = new Map();
  const idToFiberMap: Map<number, Fiber> = new Map();
  const primaryFibers: Set<Fiber> = new Set();
   When profiling is supported, we store the latest tree base durations for each Fiber.
   This is so that we can quickly capture a snapshot of those values if profiling starts.
   If we didn't store these values, we'd have to crawl the tree when profiling started,
   and use a slow path to find each of the current Fibers.
  const idToTreeBaseDurationMap: Map<number, number> = new Map();
   When profiling is supported, we store the latest tree base durations for each Fiber.
   This map enables us to filter these times by root when sending them to the frontend.
  const idToRootMap: Map<number, number> = new Map();
   When a mount or update is in progress, this value tracks the root that is being operated on.
  let currentRootID: number = -1;
  function getFiberID(primaryFiber: Fiber): number {
    if (!fiberToIDMap.has(primaryFiber)) {
      const id = getUID();
      fiberToIDMap.set(primaryFiber, id);
      idToFiberMap.set(id, primaryFiber);
    }
    return ((fiberToIDMap.get(primaryFiber): any): number);
  }
  function getChangeDescription(
    prevFiber: Fiber | null,
    nextFiber: Fiber,
  ): ChangeDescription | null {