I interviewed at Dropbox earlier this year and the behavioral component surprised me a bit. I'd expected a fairly boilerplate STAR-format round and got something a little more nuanced.
Dropbox has a set of values that they actually use as the behavioral framework. The most prominent ones that came up in my rounds were around craft (they care about doing work well, not just shipping), and around collaboration and conflict resolution.
Specific questions I was asked: Tell me about a time you disagreed with a technical decision made by a more senior engineer. What did you do. Describe a project where the requirements changed significantly mid-execution. How did you handle it. Tell me about a time you had to make a tradeoff between shipping fast and doing it right. Walk me through a collaboration that was harder than expected and what you learned.
A few observations. First: they really want specifics. Vague answers about "working through it" didn't land well in practice, I could tell from the follow-ups I got. They kept asking for concrete things: what did YOU do, what was the actual outcome, what would you do differently.
Second: the craft question (fast vs right) seemed to be almost universally part of the loop. I think they're filtering for engineers who have thought about quality intentionally, not just people who say they care about it.
Third: I was coming back from a career gap (took time for caregiving) and they were genuinely not weird about it. One interviewer asked me to walk through my gap year in a normal, curious way, not an accusatory one. That mattered to me.
Overall, prep your STAR stories but make sure they're specific and honest. Generic worked great at other companies, here the interviewers dug.