Warn about lying links #4588

This link is a liar!

• https://github.com/sindresorhus

[https://github.com/sindresorhus](https://octolinker-demo.vercel.app/sindresorhus)

If a link in a markdown area appears as a URL, we can ensure that the shown origin matches the real origin or its no-www version. If not, we can show a warning icon with “origin mismatch” tooltip or something similar, like this link opens “other.domain.com”