In Nuxt 2, using nuxt generate, we could either manually provide routes to generate or depend on the (later added) crawler to find them.

For manual mode, it was possible to use generate.routes option to provide an async function prefetching them. While this functionality is needed in general, adding async logic to nuxt.config is kinda an anti pattern that we are trying to avoid in Nuxt 3 so there might be better ideas.

Ref: #13939