View plugin privacy registry
From MoodleDocs
This page lists all the installed Moodle (core and additional) plugins and whether they implement the Moodle privacy API.
If a plugin does not implement the Moodle privacy API and stores any personal data, it will not be able to be exported or deleted through Moodle's privacy system.
All core Moodle 3.5 plugins do implement the Moodle privacy API:
Some 3.5 additional plugins do, but others don't.
Most additional plugins that do currently state that "The xxxx plugin does not store any personal data."