Self-hosting is becoming a big topic today as some people want to control their own data or learn more about how technology works by running their own services at home. ICANN reserves the use of the .international top-level domain name (TLD) on the Internet in an effort to make it easier for people to do so. It's worth noting that the IEEE has reserved .home.arpa for internal home use via RFC8375, but .internal is a more concise name.
Earlier this year, ICANN solicited comments on the proposed TLD and, with no concerns raised (other than the length of the TLD), the TLD was referred to the ICANN Board for further consideration. According to TheRegister, ICANN has now approved the domain name, which means that no one on the Internet can anymore register a domain name like neowin.internal.
What you may not know is that there are already similar settings for specific IP addresses that are not allowed to be routed on the Internet. As defined in RFC1918, addresses in the ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are for internal network use only. The new ICANN standards mean you can now host your own DNS and Certificate Authority (for encryption) within your internal network using these addresses and TLDs without having to worry about anything hacking into your network in the future.
The most important thing to note if you decide to use this new top-level domain is that this will make services like Let'sEncrypt unavailable on it, since there is no specific owner for any subdomain of .internal. You can create your own domain name if you wish, but if you want a certificate known to the world, you still have to purchase a public domain name.