With HTTP cache partitioning, prefetching cross-origin resources isn't very useful, so we should probably add a web console warning.
See also the discussion at https://github.com/w3c/resource-hints/issues/82. It's not entirely clear to me if this feature still has a use in this brave new privacy-first world. (That is, how often is it used for same-origin navigations?)
Yeah that's a good point.