You have the right to a copy of what’s recorded about you. That copy contains your profile, your measurements, your workouts and sets, your answers to forms, your notes and the links to your progress photos.
This is different from deleting. Requesting a copy changes nothing about your account; your data simply stays. If you actually want everything gone, see Deleting your account.
You request it under Profile → Your data and who has looked at it. You get a link by email at your account’s address; it works for 24 hours and expires after that. Feel free to request a new one if you’re too late.
You get a zip file. It contains gegevens.json with everything recorded about you, and a fotos folder with your progress photos.
The file isn’t attached to the email, and that’s not because it would be too big: it contains notes from your care provider, and those shouldn’t sit in a mailbox forever.
You can request three copies a day.