ssh_config(5) on macOS
The text c889478d1ed8, as Mac OS X 10.4.7.x86, Mac OS X 10.4.7.ppc, Mac OS X 10.4.6.x86, Mac OS X 10.4.6.ppc, Mac OS X 10.4.5.x86, Mac OS X 10.4.5.ppc, Mac OS X 10.4.4.x86, Mac OS X 10.4.4.ppc, Mac OS X 10.4.3, Mac OS X 10.4.2, Mac OS X 10.4.1, Mac OS X 10.4 shipped it.
OpenSSH SSH client configuration files