Just as an extension of last rant to explain how much fun it is to keep up with Apple's security through obscurity bullshit.
AFAIK this full disk access (FDA) feature was touted to protect a user's data on macOS. Programs that want to access those files need to request the user's permissions to do so. Now to the fun part: Apple is not providing any API. A staff member suggested, that you should only try to access the files your app needs and if you can't as for the user's allowance. One should not use some fixed files and try to access them, because their locations might change, as well as their (UNIX file) access rights (ACL), or if they fall under FDA. Not to speak about the other security features that might hinder you accessing files (you might be sandboxed, or the files might be subject to SIP/rootless).
Honestly, you should be starting to take drugs, if you want to stay sane. I mean UNIX ACL are weird enough: e.g. you can make a directory only readable for root such that a user cannot list the files inside, but you can place files inside that the user can read (if she knows about their existence). On macOS you'll never know. You may have all the rights to access a file,.. but Apple will only give you the finger.
As they always do to us developers.