Was referred by a current employee.

Got very mixed opinions on the hiring manager. It was not clear if he was playing with me or if he was just like that personally. Also, he wasn't present on the day of the interview, so I haven't met him in person. Hopefully, I won't need to.

Got positive opinions on the team and the project manager. Very technical people, with mixed backgrounds. Quite senior people. It was quite easy to start understanding each other without too many words.

Some of the interview sessions were held by two people simultaneously, including remote ones. I don't think it worked out too well. It was, probably, OK as a training session for fresh interviewers, but none of the guys was new to interviewing.

Nothing unexpected. The interview is very similar to what you would get at Google or any other large technical company.

Algorithms, data structures, system design, thinking out loud.

Refresh your stuff on your resume and be prepared to answer questions.