This is largely a question for Thiago, but feel free to chime in if you can help...
The URL Rewriting feature in T5.1 was added for TAP5-577 and in the comments Thiago said "Each rule will be applied, but each one can decide to really rewrite the URL/link or not. If you take a look at the tests (app5.services.AppModule), you see rules that only apply to incoming URL requests and ignore the others and rules that only apply only for generated links. And there is even one rule that applies to a single URL." I've just been looking at the tests and I can't see any rules that will apply only to generated or incoming links. What am I missing? Can anyone clue me in?