From 3ca12abf679f134bbe4ba474e14473fc483fc25b Mon Sep 17 00:00:00 2001
From: Anne van Kesteren
A user agent holds a top-level traversable set (a set of top-level traversables). These are typically presented to - the user in the form of browser windows or browser tabs.
+A user agent holds a top-level traversable set (a + set of top-level traversables). These are + typically presented to the user in the form of browser windows or browser tabs.
To get the top-level traversable of a navigable inputNavigable: