## 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
pendingStringTable.forEach((value, key) => {
      operations[i++] = key.length;
      const encodedKey = utfEncodeString(key);
      for (let j = 0; j < encodedKey.length; j++) {
        operations[i + j] = encodedKey[j];
      }
      i += key.length;
    });
    if (numUnmountIDs > 0) {
       A
      operations[i++] = TREE_OPERATION_REMOVE;
       T
      operations[i++] = numUnmountIDs;
       F
       T
       S
      for (let j = pendingRealUnmountedIDs.length - 1; j >= 0; j--) {
        operations[i++] = pendingRealUnmountedIDs[j];
      }
       Fill in the simulated unmounts (hidden Suspense subtrees) in their order.
       (We want children to go before parents.)
       They go *after* the real unmounts because we know for sure they won't be
       children of already pushed "real" IDs. If they were, we wouldn't be able
       to discover them during the traversal, as they would have been deleted.
      for (let j = 0; j < pendingSimulatedUnmountedIDs.length; j++) {
        operations[i + j] = pendingSimulatedUnmountedIDs[j];
      }
      i += pendingSimulatedUnmountedIDs.length;
       T
      if (pendingUnmountedRootID !== null) {