drogus/rails — comment on commit 8221cb6d679a6daac530428b746716b48aa3faca
File: railties/lib/rails/application/route_inspector.rb line 45
By drogus:

I didn't want to assume that every rack app that responds to routes is an Engine, it may be something else. But if you think it's safe, you're right, I could just check if it responds to routes