This item is acquired in-game. See its sources below.
A Rare Miscellaneous, item level 35, requires level 10, binds when picked up.
First seen in build 12.0.7.68887 (Midnight (patch 12.0.7)).
8 quests list Outpost Building Assembly Notes among their rewards in Blizzard's quest data.
Goc's Trophy, 
Goc's Eye, 
Might of the MagnaronGoc's Trophy, 
Genesaur's Greatness, 
Commander Gar's Iron InsigniaGoc's Trophy, Genesaur's Greatness, Commander Gar's Iron InsigniaGoc's Trophy, Genesaur's Greatness, Commander Gar's Iron InsigniaRead from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
Outpost Building Assembly Notes uses icon file 133740, which 155 other items also use. The 8 closest by item ID:
The Big Book of Garrison Blueprints ID 116827 · Miscellaneous "First edition."Research Journal ID 115272 · Quest "The scientific ramblings of a highly gifted, or incredibly insane mind. It's difficult to tell which...."Book of Garrison Blueprints ID 118215 · MiscellaneousSecret of Draenor Alchemy ID 118700 · Trade Goods · item level 40 "Trade for recipes at your Garrison profession building or in Ashran."Diary of Balldir Deeprock ID 118703 · Miscellaneous · item level 35 "The waterlogged pages have mostly faded, but you can make out some pieces about field testing a poison...""01000010" ID 114013 · Miscellaneous "This publication is written in binary code. It contains pictures of malfunctioning fluxfire felines and has..."Secret of Draenor Enchanting ID 119293 · Trade Goods · item level 40 "Trade for recipes at your Garrison profession building or in Ashran."Secret of Draenor Inscription ID 119297 · Trade Goods · item level 40 "Trade for recipes at your Garrison profession building or in Ashran."Blizzard numbers items as they are created, so the named items next to ID 116394 (116389 to 116399) were usually added in the same batch as Outpost Building Assembly Notes: the same quest line, zone, vendor or reward set.
Thogar's Imperialistic Spire ID 116389 · Weapon - Staff · item level 44
Battle Medic's Wand ID 116390 · Weapon - Wand · item level 44
Blackhand Forgehammer ID 116391 · Weapon - Two-Handed Mace · item level 44
Big Bag of Booty ID 116392 · Miscellaneous "Generous Dan wasn't captain of the Dread Crew for long, but is still regarded as the best captain ever."
Dagger of the Shattered Crucible ID 116393 · Weapon - Dagger · item level 44
Comprehensive Outpost Construction Guide ID 116395 · Miscellaneous · item level 35 "Sought by architects in Ashran. Field research regarding building and maintaining outpost structures, with..."
LeBlanc's Recorder ID 116396 · Miscellaneous "Treasured by the bards of Azeroth."
Swift Riding Crop ID 116397 · Consumable · item level 40
Flimsy X-Ray Goggles ID 116398 · Consumable · item level 40
Emerald Sunglasses ID 116399 · ArmorRead from the World of Warcraft client build files: Item, ItemSparse, Lock, Holidays, AreaTable and CollectableSourceVendor.
TheWoWDB
