The daemon is automatically started by udev upon hotplug of an iOS
device and exits if the last device was unplugged.

When usbmuxd is running it provides a socket interface at
	
	/var/run/usbmuxd

that is designed to be compatible with the socket interface that is
provided on macOS.

You should also create an usbmux user that has access to USB devices on
your system:

	useradd -s /bin/false -d /dev/null -g users usbmux

Alternatively, just pass a different username using the -U argument.