It's nearly never as simple as a one-liner answer like the one above. The whole point is to go through the entire funnel of PM skills in that 45min interview, from creating a vision, isolating a customer, identifying pain points to actually thinking of solutions and prioritizing within them before talking about the execution. So for instance here.. a vision could be a library that's "always available" i.e. based in the cloud, and "contextually relevant", so available nuanced to the context of what you're looking for. Etc. Best way to learn how to answer these questions is direct practice with Google PMs so they can tell how what to do and what not to do.. Prepfully and interviewing io both have a couple of coaches who do this.