Firefox doesn’t get served WebP version HTML

Hi guys,

This is more of a Firefox issue, but was wondering if anyone knows if this is by design or an omission?

In Firefox (67.x), the request header for a page doesn’t include image/webp. As a result Cache Enabler won’t serve the WebP version of the HTML.
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

However Chrome does and webp images are served.
accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3

I suppose a workaround would be to add some rewrite codes in htaccess if Firefox won’t be changing their request.