The ___domain name is being converted to PunyCode (https://en.wikipedia.org/wiki/Punycode). This is a defence developed to prevent spoofing of ___domain names using indistinguishable characters from other character sets than ASCII. Before this was fixed by browser developers, it was possible to execute an IDN homograph attack (https://en.wikipedia.org/wiki/IDN_homograph_attack) and spoof sites using characters that looked like e.g., google.com/paypal.com when they rendered in your browser address bar, but were actually a completely different ___domain as far as automated systems were concerned.

Edit: typo.

It's an IDN: http://en.wikipedia.org/wiki/Internationalized_domain_name

That's how internationalized domains work.

Wikipedia: https://en.wikipedia.org/wiki/Uniform_Resource_Locator#Inter...

Interestingly, Hacker News doesn't support this standard, and the link on the front page shows the unfriendly version.

It's because IDN domains became a standard after tables stopped to be used in page layouts </sarcasm>