They basically contain operations previously available via 'nmcli nm'.
'nmcli nm' is still kept for backward compatibility.
Usage:
nmcli switch [all|networking|wifi|wwan|wimax [on/off]]
nmcli general [status|permissions]
Examples:
nmcli switch all - show all switches
nmcli switch wifi off - switch Wi-Fi off
nmcli g s - show NM status
nmcli g p - show NM permissions