> Looking at the headers via curl, I see "expires" with the current date and time (ie, it's already expired), a max-age tag of 50 minutes. I'm not seeing one ye

> Looking at the headers via curl, I see "expires" with the current date and time (ie, it's already expired), a max-age tag of 50 minutes. I'm not seeing one year anywhere. Take a look at the version of the doc which is served from the AMP cache: https://cdn.ampproject.org/c/s/lolware.net/2017/07/04/amp-bloat.html https://cdn.ampproject.org/c/s/lolware.net/2017/07/04/amp-bl... I like to think of PageSpeed Insights like the output of a good linter. No linter is or can be perfect. The issues reported are good things to consider and are correct for the majority of times that they trigger, but not in all cases. This is one of those cases. > CORS The best fix here might be a more useful response in the dev console. Plenty of sites, especially on dev servers, don't have any CORS headers at all, so this does work in those cases. I'd still recommend one of the other validation methods which work fine with any CORS setup.