I met with the advisor to learn about the opportunity and was asked to convey my interest via email in a week. After doing a brief research on potential advantages of working on the proposed project, I conveyed my interest, following which I was called for an on-site interview, which was scheduled for in about 4 weeks. All travel arrangements were made by the employer. It was almost a day-long interview (8 AM - 2 PM), and included one-on-one with graduate students, postdocs and research faculty and an hour-long presentation session later that afternoon. The interview ended with a one-to-one interview with the advisor himself.

Pretty casual and straightforward. Welcoming faculties and staffs. The interview is more like a confirmation once the decision is made by the hiring personnel. Just providing a data point here.