Archive.is does embed links to mail.ru but that requires javascript. The site itself does not require javascript which is why I suppose I never really notice it. I could see firewall vendors flagging it for that reason.
Interesting. Oh also forgot the question about the vendor but I'm pretty sure it's zscaler? Unless there's something else behind the scenes that's catching sites, there's no branding on the error page other than my org's, it's completely whitelabeled.
