This seems like a set of questions for Analysts, rather then Engineers. If you apply for a ML SWE role, these are unlikely to be the questions you get, though

This seems like a set of questions for Analysts, rather then Engineers. If you apply for a ML SWE role, these are unlikely to be the questions you get, though with a company as large as Google, who knows what your interviewer will bust out. GBM is trees, and I think the question is to explain why you would want trees, but I think the trick for fitting arbitrary differentiable loss functions in a GBM is pretty nifty.