To support building for Apple ARM64 which was introduced in MacOS 11 OpenSSL added support for Apple ARM in 1.1.1 (61168b5b8d). Python added support for MacOS 11 in 3.7.8+, 3.8.4+, 3.9.0+ (https://github.com/python/cpython/pull/21113 and backports).
61168b5b8d