## 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
hook: DevToolsHook,
  rendererID: number,
  renderer: LegacyRenderer,
  global: Object,
): RendererInterface {
  const idToInternalInstanceMap: Map<number, InternalInstance> = new Map();
  const internalInstanceToIDMap: WeakMap<
    InternalInstance,
    number,
  > = new WeakMap();
  const internalInstanceToRootIDMap: WeakMap<
    InternalInstance,
    number,
  > = new WeakMap();
  let getInternalIDForNative: GetFiberIDForNative = ((null: any): GetFiberIDForNative);
  let findNativeNodeForInternalID: (id: number) => ?NativeType;
  if (renderer.ComponentTree) {
    getInternalIDForNative = (node, findNearestUnfilteredAncestor) => {
      const internalInstance = renderer.ComponentTree.getClosestInstanceFromNode(
        node,
      );
      return internalInstanceToIDMap.get(internalInstance) || null;
    };