I participated in a couple of rounds of phone interviews. They were very conversational/casual. All the employees I spoke with seemed pretty young and it was definitely a gauge for personality fit.

Three months, four rounds, one take-home, eight interviews. Last round was a half-day onsite, then several weeks of radio silence, then an impersonal rejection. Multiple people from the recruiting team were in touch for scheduling at different stages, so it was unclear who the main recruiting contact was until later in the process. No information about interviews was provided until the day of the last round (e.g. the initial invitation for a first interview was generic enough to seem like an HR screening call, but it turned out to be a first round with the hiring manager). Definitely felt like things could have been condensed and more transparency throughout the process could have softened the death blow at the end.