This is a diff of the FreeBSD base system ssh (crypto/openssh) against OpenSSH 7.9p19.0p1, for reference.
Generated via `git diff -U9999 --diff-filter=M vendor/openssh/9.0p1 HEAD:crypto/openssh`
`diff -U9999 -purw ~/src/openssh-7.9/ crypto/openssh | egrep -v '^Only in|^diff -U'`