I remember the case in which one guy (I think he was Irish) did send that request to Facebook and got a over one thousand page long response.
Then, there was a shit ton of persons from Europe (like, dozens of thousands) who tried to do the same through a combined court order in Vienna. Then, the court in Vienna decided that this issue was "not admissible on procedural grounds". Then, those thousands of people got generic responses like: "You can download every data we store on you by going into your settings...". Then there was an appeal to that decision and then the whole thing died out.
Then, there was a shit ton of persons from Europe (like, dozens of thousands) who tried to do the same through a combined court order in Vienna. Then, the court in Vienna decided that this issue was "not admissible on procedural grounds". Then, those thousands of people got generic responses like: "You can download every data we store on you by going into your settings...". Then there was an appeal to that decision and then the whole thing died out.
I found the website that organized this: http://europe-v-facebook.org/EN/en.html