Using these instructions here I’ve now configured webmin on “monkey” by adding my username to /etc/webmin/miniserv.users and /etc/webmin/webmin.acl to allow me to access https://monkey:10000.
hippy@monkey:~$ pfexec more /etc/webmin/miniserv.users
root:x:0
hippy:x:101
hippy@monkey:~$ pfexec more /etc/webmin/webmin.acl
hippy: acl adsl-client apache at backup-config bandwidth bind8 bsdexports burner cfengine change-user cluster-copy cluster cron cluster-passwd cluster-shell cluster-software cluster-useradmin cluster-usermin cluster-webmin cpan cron custom dfsadmin dnsadmin dovecot exports fdisk fetchmail file filter firewall format frox fsdump grub heartbeat hpuxexports htaccess-htpasswd idmapd inetd init inittab ipfilter ipfw ipsec jabber krb5 ldap-client lilo lpadmin lvm mailboxes mailcap majordomo man mon mount mysql net nis openslp pam passwd phpini postfix postgresql ppp-client pptp-client pptp-server proc procmail proftpd pserver qmailadmin quota raid rbac samba sarg sendmail sentry servers sgiexports shell shorewall smart-status smf software spam squid sshd status stunnel syslog-ng syslog telnet time tunnel updown useradmin usermin vgetty webalizer webmin webminlog wuftpd xinetd zones