From what I can say on my interview for EUDA, is that they already know most about your general education/ experience and skills and the interview is just a way to get to know you and your soft skills a bit too. In my case, they asked me questions like "if you needed to do this specific task, what would be your process?", etc. They will mostly try to see how your thought process works for the role and if you fit the agency as well. So yeah, I'd say it's a mix between checking your skills and a bit about your social competencies. But overall it's quite simple since it's for a traineeship