Why is "/hierarchy" part of xpaths generated by inspector in the latest (July 2017) version of the Appium app?

Why does the latest version of Appium app (which was referred to as version 1.6 for the months before its release, but whose About view shows 1.1.0-beta.4) show Android xpaths beginning with /hierarachy, e.g.,

/hierarchy/android.widget.FrameLayout/android.widget.LinearLayout/android.widget…

As far as I know, hierarchy is not valid in an xpath.