marked out TS control markings the document was originally classified as Top secret no Foreign nationals hence the TOP SECRET//NOFORN at the top
the marked out portion is (TS//NF) marked out with X's hence TOP SECRET//NOFORN at the top of the document the b1,b3 etc etc are the reasons why that section was redacted the redaction code (b) has to do with information relating to foreign governments
more specifically the codes b1 b3 and b7 are in order
(b) (1) Reveal the identity of a confidential human source, a human intelligence source, a relationship with an intelligence or security service of a foreign government or international organization, or a nonhuman intelligence source; or impair the effectiveness of an intelligence method currently in use, available for use, or under development
(b) (3) Reveal information that would impair U.S. cryptologic systems or activities
(b) (7) Reveal information that would impair the current ability of United States Government officials to protect the President, Vice President, and other protectees for whom protection services, in the interest of the national security, are authorized