Angular guide: different types of NgModules

Question

I was reading the Angular guide about Guidelines for creating NgModules and I could not understand the difference between Routed and Routing NgModules. In my apps I always used the "standard" (?) main module + routing module pair for features, and I now understand these are the Domain NgModule and the Routing NgModule. I could easily understand Service, Shared and Widget NgModule. I cannot understand at all the what, why and how of the Routed NgModule. Is someone able to shed some light? Thank you!