## 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
|};
type InspectElementNotFound = {|
  id: number,
  type: 'not-found',
|};
export type InspectedElementPayload =
  | InspectElementFullData
  | InspectElementHydratedPath
  | InspectElementNoChange
  | InspectElementNotFound;
export type InstanceAndStyle = {|
  instance: Object | null,
  style: Object | null,
|};
export type RendererInterface = {
  cleanup: () => void,
  copyElementPath: (id: number, path: Array<string | number>) => void,
  findNativeNodesForFiberID: FindNativeNodesForFiberID,
  flushInitialOperations: () => void,
  getBestMatchForTrackedPath: () => PathMatch | null,
  getFiberIDForNative: GetFiberIDForNative,
  getDisplayNameForFiberID: GetDisplayNameForFiberID,
  getInstanceAndStyle(id: number): InstanceAndStyle,
  getProfilingData(): ProfilingDataBackend,
  getOwnersList: (id: number) => Array<Owner> | null,
  getPathForElement: (id: number) => Array<PathFrame> | null,
  handleCommitFiberRoot: (fiber: Object, commitPriority?: number) => void,
  handleCommitFiberUnmount: (fiber: Object) => void,
  inspectElement: (
    id: number,