ASP.NET routing is responsible for mapping incoming browser requests to particular MVC controller actions. You can find more information about routing here. GrandNode has an IRouteProvider interface which is used for route registration during application startup. All core routes are registered in the RouteProvider class located in the Grand.Web project.
If your plugin requires a registered route, just add a class named as "RouteProvider.cs"
Below is an example of properly defined RouteProvider, your class will need to inherit from IRouteProvider
Routes registration will occur on beginning of application start in global.asax.