/usr/share/upstart/sessions/indicator-messages.conf is in indicator-messages 13.10.1+17.04.20170120-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | description "Indicator Messages Service"
start on indicator-services-start
stop on desktop-end or indicator-services-end
respawn
respawn limit 2 10
exec $SNAP/usr/lib/x86_64-linux-gnu/indicator-messages/indicator-messages-service
|