Steve, you've missed the point: EFF (https://www.eff.org/https-everywhere/faq) are providing a whitelist of sites:
"HTTPS Everywhere is a Firefox, Chrome, and Opera extension that encrypts your communications with many major websites, making your browsing more secure."
It is nothing really to with Xara-designed sites; you would still have to pay for an htpps site capability.

Acorn