It could be something like a Wi-Fi router’s configuration page, or a page within an internal server.
With a new TLD, ICANN wants to change this.
After a consultation process involving 35 candidate strings, ICANN settled on two viable options: .PRIVATE and .INTERNAL.
Arol Wright / How-To Geek
Ultimately, ICANN announced .INTERNAL as its preferred choice.
Even ones that don’t exist, as a matter of fact.