Use it for questions about the angular 2 or 4 router-outlet element.
The router-outlet is part of the routing-system of angular 2 and above. Depending on the navigated route, a specific component can be displayd in a router-outlet.
Multiple <router-outlet/>-tags are possible in one component if you name at least all but 1 of them. Nested router-outlets working together with the child-property of routing-objects in the route-config of a NgModule
