Help with some type declaration

I'm using create-t3-turbo and in expo/src/screens/home.tsx, PostCard component's prop type declaration is as follows: post: inferProcedureOutput<AppRouter["post"]["all"]>[number]; What I don't understand is what the [number] at the end means. I understand that the type of post is the inferred output of AppRouter["post"]["all"], but to my understanding, that output is not an array of numbers?