The ERA website suggests we go to their partner website, Traildino, to get more information on the european routes. Indeed, in the ERA website, there’s close to no information on the routes themselves, except for a really crude map.
Traildino has a lot of information about hiking trails all around the world. It has comments, ratings, some maps, references and links to experiences on the trails.
I am using Traildino to set up my route on a big scale. I see which “Grande Randonée” the E5 corresponds to and look at those GRs individually.