/lib/live/boot/0110-debug is in live-boot 3.0.1-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | #!/bin/sh
#set -e
Debug ()
{
	for _PARAMETER in ${_CMDLINE}
	do
		case "${_PARAMETER}" in
			live-boot.debug|debug)
				LIVE_DEBUG="true"
				;;
		esac
	done
	case "${LIVE_DEBUG}" in
		true)
			;;
		*)
			return 0
			;;
	esac
	# Write the trace output
	set -x
}
 |