Nothing special, that's how urls with unicode, non ascii chatacters look like. It's called punycode, more info: https://en.wikipedia.org/wiki/Internationalized_domain_name
Emoji domains work the same, e.g. ❤️🍺.ws is the same as http://xn--qei8618m.ws/
Sailfish has Aliendalvik for android app support, it's proprietary. I've read good things about it: https://blogs.gnome.org/jdressler/2023/12/20/a-dive-into-jolla-appsupport/