To get information about the behaviour of visitors, Ackee is used. This analytics software gives general insight about visitors, but does not track them, and does not store any personally identifiable information.
Go to their documentation to find out what Ackee collects.
To get information on how well the site is performing, as well as capture any errors so that they can be resolved, A self-hosted instance of Sentry is used. No personally identifiable information is stored, and any information that is stored is removed after 90 days, or after the issue is resolved.
You can opt-out of performance metrics with Sentry by enabling Do Not Track in your browser.