Описание тега app-route

In its typical usage, a app-route element consumes an object that describes some state about the current route, via the route property. It then parses that state using the pattern property, and produces two artifacts: some data related to the route, and a tail that contains the rest of the route that did not match.

Reference: https://www.webcomponents.org/element/PolymerElements/app-route