A PDF copy of the Manual is included in the article. "This is the book that sets out the regulatory guidelines used by the ATF investigators who are responsible for examining and investigating FFL records." If you have an FFL license, this may be of interest.
https://www.ammoland.com/2019/11/at...-obtained-via-goa-foia-request/#ixzz679jqnfnV
https://www.ammoland.com/2019/11/at...-obtained-via-goa-foia-request/#ixzz679jqnfnV