Answer by tripleee for What does 'set -e' mean in a Bash script?

I'm belatedly posting a separate answer about the specific code in the question. It has multiple issues.

# Automatically added by dh_installinit

This is slightly misleading, in that the author of the script has apparently modified the code which was actually automatically added.

if [ "$1" = install ]; then

The preinst script will run in multiple circumstances, and receive an argument which indicates which scenario is causing it to be called. This section will get run if the action is install (and not, for example, upgrade or abort-upgrade, which are the other two possible values; see https://www.debian.org/doc/debian-policy/ch-maintainerscripts.html)

   if [ -d /usr/share/MyApplicationName ]; then     echo "MyApplicationName is just installed"     return 1   fi

This seems suspicious. The echo command might not be printing to anywhere useful, and return 1 causes the entire installation to fail.

More tangentially, MyApplicationName has aberrant capitalization; a typical value would be more like my_application or my-application

   rm -Rf $HOME/.config/nautilus-actions/nautilus-actions.conf   rm -Rf $HOME/.local/share/file-manager/actions/*

These too seem highly suspicious. The package management system should not touch any non-system files, for any user. Moreover, $HOME is probably going to be /root when this script runs, so whatever the author hoped to accomplish here is probably not actually going to happen.