Max-age=0 means that the reaction is immediately stale, and ought to-revalidate signifies that it need to not be reused without having revalidation after it truly is stale — so, together, the semantics appear to be similar to no-cache. That's a thing I've hardly ever taken to heart right until now. https://coldfirecart17282.total-blog.com/the-smart-trick-of-cold-fire-carts-that-no-one-is-discussing-61671453