No other instances.
root@mail1:~# sudo grep -r /etc/ssl/private /etc
/etc/postfix/main.cf:#smtpd_tls_cert_file = /etc/ssl/private/fullchain.pem
/etc/postfix/main.cf:smtpd_tls_cert_file = /etc/ssl/private/fullchain.pem
/etc/postfix/main.cf:#smtpd_tls_key_file = /etc/ssl/private/privkey.pem
/etc/postfix/main.cf:smtpd_tls_key_file = /etc/ssl/private/privkey.pem
/etc/postfix/main.cf:#smtpd_tls_CAfile = /etc/ssl/private/fullchain.pem
/etc/apache2/sites-available/default-ssl.conf: SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key