## 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 internalInstance = args[0];
        if (getElementType(internalInstance) === ElementTypeOtherOrUnknown) {
          return fn.apply(this, args);
        }
        const id = getID(internalInstance);
        parentIDStack.push(id);
        try {
          const result = fn.apply(this, args);
          parentIDStack.pop();
          
          recordUnmount(internalInstance, id);
          return result;
        } catch (err) {
          parentIDStack = [];
          throw err;
        } finally {
          if (parentIDStack.length === 0) {
            const rootID = internalInstanceToRootIDMap.get(internalInstance);
            if (rootID === undefined) {
              throw new Error('Expected to find root ID.');
            }
            flushPendingEvents(rootID);
          }
        }
      },
    });
  }
  function cleanup() {