it's in /usr/libexec: check /var/log/scripts/x11-ssh-askpass-1.2.4.1-x86_64-2
Code:
$ cat /var/log/scripts/x11-ssh-askpass-1.2.4.1-x86_64-2
( cd usr/man/man1 ; rm -rf ssh-askpass.1x.gz )
( cd usr/man/man1 ; ln -sf x11-ssh-askpass.1x.gz ssh-askpass.1x.gz )
( cd usr/libexec ; rm -rf ssh-askpass )
( cd usr/libexec ; ln -sf x11-ssh-askpass ssh-askpass )