GitHub hosts code repositories for countless different projects, from personal websites topopular apps like VLC Media Player.
In other words, part of the key used for connecting to GitHub repositories was accidentally published.
As a result, any public/private key pairs created before that time (e.g.
someone who already set up GitHub Git access on their PC) will now show a warning.
Browsing and downloading code from GitHub’s website in your web app still works as usual.
Source:GitHub
Via:The Register