First an online interview, asked generic questions about technical skills, why wanted to work there, and personal projects, along with other questions.
Second interview was an assessment centre, on premises. Individual tasks as well as a group design task with the other candidates.
Whole experience felt very friendly and interesting. Challenges were intense, but everyone assessing clearly wanted the candidates to do their best, and would give prompts to help if it meant that they could more wholly assess skill level.
Thank you Labman!