Secret documents

Secret documents, also known as secret docs, confidential docs or in some cases design specs, are a type of document that contains highly classified information, and as such are usually kept under close guard. These documents are usually packed in a manilla envelope with a red "[Top Secret]" stamp on it, although they also can come in satchels, and contain information such as schedules for various locations, maps relating to a facility with updates on it, or even blueprints.

Soviet Union
During the Cold War, the CIA planned a mission where one of its agents would impersonate GRU Major Ivan Raidenovitch Raikov, infiltrate a Soviet base, and steal documents, but it was cancelled. In addition, documents detailing Metal Gear, as well as designs of the Shagohod with Aleksandr Leonovitch Granin's commentary were submitted to the CIA by Philosophers agent Ocelot shortly before Granin's arrest.

San Hieronymo Peninsula
During the San Hieronymo Takeover, the renegade FOX unit as well as former members of the Red Army kept guard of various classified documents in regards to its activities and locations of key establishments on the peninsula's Soviet missile base. A Soviet officer stationed at the Soviet patrol base was charged with guarding a trajectory printout of the ICBMG's launch coordinates as well as the date of the launch, although Naked Snake/Big Boss managed to steal it. Big Boss, when trying to locate malaria medicine, also procured lists of outbound materials headed for a research laboratory in the mountains and used both the list and a Hind that was searching for them to locate it. Afterwards, spy units belonging to Big Boss's resistance movement managed to uncover locations of various classified documents in areas that they were stationed in, as well as either reporting their location or even submitting some of the classified documents themselves. Classified documents uncovered during the mission via the resistances spy units included a transportation route map that displays the locations of the town, the harbor, the rail bridge that connects the two halves of the peninsula, and the peninsula's main security base, as well as a supplement to the map that indicated a rotation schedule for Soviet soldiers manning a newly installed checkpoint on the rail bridge; a map to the nuclear warhead storage facility, as well as outdated reports about the storage facility expecting a team to arrive to take the warheads; a map that gives the route and location to the guest house that was supplied to the rail bridge guards; a map that gave the location to the western wilderness high-security prison; blueprints of the missile silo, as well as blueprints for the ICBMG's booster rocket/Saturn V, which were procured under Ghost/Nikolai Stephanovich Sokolov's request and delivered to him. The CIA Director later managed to utilize the half of the Philosophers Legacy he gained six years earlier to gain documents relating to the identities of various Philosophers agents so he'd revive the organization even if America ends up destroyed by the recently launched ICBMG, and later packed them into a suitcase to bring them down to the underground shelter underneath the CIA Headquarters at Langley to ensure its survival, but it ended up stolen by Ocelot who also killed the CIA Director and staged it as a suicide.

Costa Rica/Peace Sentinels/Militaires Sans Frontieres
Design specs for various weapons systems and equipment were scattered around Costa Rica and Nicaragua. The Militaires Sans Frontieres procured several of these documents and developed their own variations of the weapons and equipment used, either by stealing them from the Peace Sentinels or by rescuing defecting researchers who supplied them with the documents for developing their own variations. In addition, the Militaires Sans Frontieres also created their own documents and used them to create their own weapons systems/equipment, at least one of which was developed before their missions in Costa Rica and Nicaragua.

United States Government/FOXHOUND
During the Outer Heaven Uprising in 1995, Solid Snake was supplied with a document during his briefing with Big Boss before proceeeding with Operation Intrude N313 documenting Gray Fox's route before he was captured. Four years later, Roy Campbell supplied Solid Snake with a classified document when briefing him on his mission to Zanzibar Land, codenamed Operation Intrude F014, that included information about the expected weather and climate conditions, enemy forces figures and information, terrain, known allies, the mission plan, various detailed steps on how to proceed with the mission, and two appended documents, one of which was a see-through 3D map of Zanzibar Land that included points indicating the various locations in the area, and the other was a photo of Kio Marv, the Czech biologist whose rescue the mission required. Six years later, Roy Campbell supplied Snake with case files on the various FOXHOUND members, as well as files relating to some of his contacts when briefing Snake on his mission to Shadow Moses. ArmsTech President Kenneth Baker also kept some classified documents in his computer files relating to Metal Gear's development, which included information on REX's railgun and portions of the true nature of its nuclear armament, some files relating to the stealth nuke, the nature of the PAL key used to activate/deactivate the warhead on REX, financial journals and some journals that indicated Baker's ulterior motive in creating REX, and some documentation relating to the history of the weapons industry during and after the Cold War, which Otacon later discovered when hacking into Baker's files.

Behind the scenes
Secret docs were first introduced in Metal Gear Solid: Portable Ops as a gameplay element to proceed to the game, most of them being used to uncover new locations on the map, including the town, rail bridge, harbor, security base, warhead storage facility, western wilderness, and guest house. In addition, with the exception of the secret doc that was procured at the Soviet patrol base near the start of the game, the secret docs usually require a spy unit to find them before they can be unlocked. The blueprints are required to recruiting Nikolai Stepanovich Sokolov. In-game coding and various hacks from Metal Gear Solid: Portable Ops indicated that both the secret docs and the blueprints were intended to also be viewable in the equipment menu, but were removed from the final version. Similar to all plot-related items, they are represented as a red and black item box.

Secret docs reappeared in Metal Gear Solid: Portable Ops Plus, although this time, their usage and manner of being procured is completely different. The secret documents are procured by shaking up a random unconscious soldier or forcing a random held-up soldier to drop his belongings on the current map of the Infinity mission. Upon gaining it, it also reveals the location of the exit of the stage.

"Confidential document (design specs for R&D Team). Details requirements for developing the ___________."

- CNFDTL DOC/design specs basic description in Metal Gear Solid: Peace Walker

"Confidential document (design specs for R&D Team). Details requirements for cultivating bananas."

- CNFDTL DOC/Banana Cultivation Instructions in Metal Gear Solid: Peace Walker

Secret docs, called "CNFDTL DOC" and "design specs," reappeared in Metal Gear Solid: Peace Walker, although this time they are utilized as a way to develop weapons systems and various equipment. In some extra ops missions, one of the focuses is to procure design specs (which have five pages). These can also be awarded upon clearing a mission, or in some cases, clearing a mission with an S-rank. Although most of them pertain to weapons and equipment building for R&D, one dealt with cultivating Bananas. In addition, various unlockable items, more specifically the Rathalos wing, the Tigrex fang, the Gear REX mucous, the Gear REX concentrate, and the Gear REX super extract, operate under a similar manner to design specs that result in the creation of the Tanegashima, the Human Slingshot Post, and sling bands rank 1, 2, and 3, respectively. The sprite for the design specs/CNFDTL DOC is reused from the model viewer display of Huey's letter.

On the Development Without Borders website, a manilla envelope styled in a similar manner to classified document envelopes, was shown on the website. Clicking on it resulted in concept art being unveiled of Big Boss with a dog.