cloud_copy

This video covers the cloud_copy rig type which simply copies a bone from the metarig to the generated rig.

This is useful for getting more granular control of your rigging, since it lets you just rig your character bone by bone - which you can just as well do without CloudRig, so this should only be used when a lot of control over the rig's specific behaviours are necessary.

You can get a written description on the wiki: cloud_copy.

Here is a playlist of the rigging live streams I mentioned in this video.