Read from the World of Warcraft client build files.
How Forged Warmonger's Jerkin Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Forged Warmonger's Jerkin suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Similar Items
The 2 items nearest to Forged Warmonger's Jerkin (item level 350) in item level among Armor > Leather, Chest slot, from item level 330 to 400.
Blizzard numbers items as they are created, so the named items next to ID 223821 (223816 to 223826) were usually added in the same batch as Forged Warmonger's Jerkin: the same quest line, zone, vendor or reward set.