The OpenBSD project maintains portable versions of many subsystems as packages for other operating systems. Because of the project’s preferred BSD license, which allows binary redistributions without the source code, many components are reused in proprietary and corporate-sponsored software projects. The firewall code in Apple’s macOS is based on OpenBSD’s PF firewall code,[6] Android’s Bionic C standard library is based on OpenBSD code,[7] LLVM uses OpenBSD’s regular expression library,[8] and Windows 10 uses OpenSSH (OpenBSD Secure Shell) with LibreSSL.[9]

https://en.wikipedia.org/wiki/OpenBSD