RFC 1918 addresses

term

networking

The private IPv4 ranges - 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 - routable inside, never on the public internet, and the reason NAT exists.

Published in 1996 as address exhaustion loomed; every home 192.168.0.1 descends from it.