It's a meta-cookie, so it's a cookie about cookies and the only one cookie which we really serve from our website. We serve cookies via our CDN, CloudFlare, so it must be agreed, too. Because of the "cookies law", website needs a new one cookie storing the info in your browser that a visitor agreed to the cookies policy. In a different way, pages would've to display the annoying info all the time. So, instead of zero cookies directly from us, you have got one + annoying banner which forces you to give the consent.
The "__cfduid" is a 3rd party cookie from Cloudflare (content delivery network). This cookie tries to detect spyware and malicious behavior.