The question was a blank environment set up to test the items on my resume that qualify as full-stack. It was a test for understanding of frontend work, deep knowledge of javascript (talking structure and best practices, callbacks, event bubbling, some obscure stuff that's actually pretty easy), database calls, structure normalization, and an understanding of computer science (theory wise, not just languages) The hardest part of the interview was paying attention to the screen during the test - I interviewed while they were in their tech stars phase so there were a ton of people running around making noise outside the room.