@phf Oh no I enjoy the conversation. And you're likely right @abbe98 pointed out to me that there is an exemption for personal notes.
My worry is that personal data that can be very damning (political views, religion, etc) is stored digitally in notes in places where there is a responsible entity (the admin owner) but the security measures are largely unknown. How many have access?
So targeted attacks to retrieve profile info can potentially uncover a lot of personal data on large instances.
My thinking was not that I would need to know what information is stored about me. The reason i request information is to learn what information is stored in that entity's databases about me.
My first thought was that admin's would have to include any personal notes (not author's of those notes) as they could hold all that info in their database.
But as @abbe98 taught me, I would never learn (at least in that scenario and according to GDPR) that info about me is stored.