I think, you need to know about it. Codeforces don't redirect automatically from http to https version, even on login form (you can open private browser session and see it on its own, just type http://mirror.codeforces.com/). Codeforces is big internet-platform, so in 2020 it's very strange.

If you use http instead of https, please stop. It's not good.

MikeMirzayanov, can you please add redirecting to the secured version? This will increase the safety of users a lot.