This is a helpful sentence the author quoted from Keller's work. I've recently asked some friends and family what mastery is and how someone shows that they are a master of something.

Keller is using the path/trail/road/highway/river metaphor to describe mastery. It's something to walk/run/swim/climb/travel/drive. Described in this way, mastery is a method and not a stand alone status. So mastery might be a method that has status or sheds status. Status is secondary to the act of engaging with the method. Mastery then requires the recompletion of the method. It is something that iterates, like a cycle or circuit so that a master may always reveal their status as such -- in terms of Keller's mastery metaphor.