It was from around 10am to around 3-4pm, many 1:1 interviews with other team members, team leader, HR, and other people in the company.
Interview with team members and the team leader was mostly technical to see how smart you are, how fast/well you can code, and other questions related to the position.
Interview with HR, and other people in the company was just general, introduce you to the company's business, what they do. And the purpose was, I think, to see how you like and fit in the company's culture.