Missing Lightning component in predictions

[Chuck Liddell]

There is a secret lightning component that is intended to be used only as a child of <lightning:progressIndicator>. The component is called <lightning:progressStep>.

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/aura_compref_lightning_progressIndicator.htm?search_text=interface

Do with this information what you will! Not sure if you can conditionally predict appropriate child components for a given parent, and not sure if you want to stick it in the master list of components you predict.