Not a hijack - the domain expired. It's showing a parking page from the registrar.

whois Domain Status: autoRenewPeriod https://icann.org/epp#autoRenewPeriod

omg abandoned site

Yes, it expired, see "Registry Expiry Date":

$ whois haiku-os.org

Domain Name: haiku-os.org

Registrar WHOIS Server: whois.namecheap.com

Registrar URL: http://www.namecheap.com

Updated Date: 2024-10-29T01:11:33Z

Creation Date: 2002-10-29T01:01:16Z

Registry Expiry Date: 2025-10-29T01:01:16Z

Maybe this domain will be renewed after all?

Maybe don't link it, then?

For the second year running, someone forgot to renew the domain. Surely they are aware of calendar reminders?

Well that sucks. Can confirm; I get a page asking me to turn off my adblocker, and the HTML is just some "lander" page and JS junk