Pretty standard "tell me your background and why you're interested in this job" type stuff. The case study was a behavioral design task. The main part of the task was quite fun, but required the candidate to choose an app to focus on (rather than being given a real or fictional app as part of the task, which is what I would have expected based on other similar tasks I've done), which introduced a lot of extra time and, critically, a lot of bias into the task.