Sat down with one of the R&D managers in the company, vibed really well, and about a lot of interesting subjects about Linux specifically- describing how FSs work in the kernel level (I hadn’t read specifically about it but my intuition led me to the correct answer, which I assume is fine as well). Questions about high performance system design and how would I design a system that does this&that putting emphasis on speed. Finally a cute programming question (wrote with a paper and pencil) and learned a lot from it. Not too easy and not insanely difficult, a great first interview.

Initial phone screen with the team leader, and then a professional interview about python internals, focuses on how data structures are implemented etc... with an exercise that's not difficult. After that there is an HR interview for the final steps.