Announcing dupReport - A Duplicati Email Report Summary Generator is a third-party tool that will read email, then notify Apprise, which can notify Slack and many other things (but seemingly not PagerDuty).
Reporting options is the main reporting section, and describes email, http, and xmpp reporting options.
Scripting options shows the option to run a script after the backup, e.g. if you have a notification client.
run-script-example.bat and run-script-example.sh show the ways your script can interact with Duplicati.
Duplicati-monitoring.com - central monitoring of multiple Duplicati instances + nice email reports is a third-party service taking HTTP notifications from Duplicati and turning them into email reports to you.