Ghost doesn't ship with any trackers, and I didn't bother to set any up, so there's not much to disclose here. I do get an anonymous count of how many people open each newsletter, and there's a built in bulk click tracker for links that I use because it lets me update links if need be, but if there's any other information like that available to me I frankly don't know how to access it. If you sign up for the email newsletter we'll have access to your email, but we're not going to do anything except send this newsletter, which is exactly what you signed up for so shouldn't be a surprise. To the best of my knowledge everything is fully compliant with GDPR.
There are a couple of affiliate links & codes scattered around that will "track" that you were recommended by me (and I may get a small financial benefit) but these always come from links I was already recommending and usually I share them because they benefit you too (i.e. getting you extra time on trials).