/lib/udev/ltsp-sound is in ltsp-client-core 5.3.7-0ubuntu2.
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 | #!/bin/sh -e
#
# udev script for ltsp-sound
(
[ -r "/usr/share/ltsp/ltsp_config" ] && . /usr/share/ltsp/ltsp_config
[ -r "/usr/share/ltsp/ltsp-init-common" ] && . /usr/share/ltsp/ltsp-init-common
DEV_BASENAME="${DEVNAME##*/}"
N="${DEV_BASENAME#controlC}"
[ -x "/sbin/alsa-utils" ] && /sbin/alsa-utils start $N
configure_sound_volume $N
) &
|