FAA Knowledge Test Question Bank - What is the source of the actual test questions? According to various online search results, the FAA test questions are not made  available to the public (page 6), but used to be.  Yet, question books claim to have the exact real questions.

How are the latest questions obtained?  I am aware of the sample questions the FAA provides, yet publications and online study sites claim to have "the most up to date" actual questions.

Are the questions available by FOI request?  Does the FAA provide the questions to publishers on some limited basis?
Years ago (35?), I taught ground school for pilots.  The question pool was not published then (it was later published, and then withdrawn), the company would send college students to take the FAA test, with the idea that they would capture certain questions, so that they could be edited and put into study guides.  

As I recall the goal was about 5 questions per student taking a test.  Most of the students were not pilot candidates, but rather engineering and even humanities students at colleges.

Attendees would also report on small differences after they had taken the written, and the company question pool would be revised.

I cannot tell you what process is used today.