The process is pretty much explained on their blogs. However, the have added another step right after the recruiter call which is a 1 hour online task with another Deliveroo engineer. The exercise is simple in the sense they are not trying to catch you out neither to test your knowledge in obscure concepts. Overall, I think it was a very positive experience and did a great job to make me feel as comfortable as possible. From my experience, the technical aspect is as important as showing leadership and other non-technical qualities.