Behavioral round at Google for a software engineering role, basically one big question about a hard project you led or worked on. Pretty standard for this type of interview but the depth they want catches you off guard if you haven't prepped a solid story.
“This question sounds straightforward until you're actually in it and realize they want all four angles covered: what made it hard (technical, scope, ambiguity, time, org stuff), your specific personal challenge, what you did about it, and then real numbers at the end.” The rest of the author's notes on Software Engineer interview at Google, Onsite - Behavioral / Leadership round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.