Navigations are saved journeys through your site. You can record one in a browser that opens from the panel, or describe the goal and the stopping point and let Trackingplan walk it once. Either way the result is saved and you can repeat it whenever you want: after a release, before a campaign, when a client asks.
A tab of suggested journeys proposes the ones worth keeping, from the pages and events of your plan.
Who it is for: anyone who checks the checkout by hand after every deploy.
Where: Navigations, in the panel. The browser stays inside the plan's domains; see Limit the agent's browser to your plan's domains.