Reference: Packages.txt

Purpose

Defines packages, which are lists of sets. This file is mostly used for assigning armor sets to drop from creatures of a particular level.

File Format

Table file. Tab separated values.
Comment character: semicolon (;)
First line is always ignored (assumed as header).

Table Columns

PackageName String. The name for this package. For lookup purposes, packages and sets should not share any names.
Auto Integer. If nonzero, this corresponds to a creature level. If a creature matching this level is killed, the sets within this package will automatically be included for drop consideration.
Flags String. Mostly obsolete. This was intended to allow extra drop considerations based on the mob's CreatureDef rarity. This feature was unused, and not tested. Be sure to test, and don't be surprised if it doesn't work correctly (or not at all).

Allows a combination of the following characters. 

Char   Description
  *    (asterisk)    Enables all flags (DEFAULT, RECOMMENDED)
  +    (plus sign)   Enable only the specified flags.
  -    (minus sign)  Enable all, but exclude the specified flags.

  a    All non-named mobs, any rarity (equivalent to 'nhel')
  A    All named mobs, any rarity     (equivalent to 'NHEL')

  n    Non-named normal mobs    (rarity=0)
  N    Named normal mobs        (rarity=0)

  h    Non-named heroic mobs    (rarity=1)
  H    Named heroic mobs        (rarity=1)

  e    Non-named epic mobs      (rarity=2)
  E    Named epic mobs          (rarity=2)

  l    Non-named legendary mobs (rarity=3)
  L    Named legendary mobs     (rarity=3)

Examples: 

+A             Only drop from named mobs.
+hHeElL        Only drop from heroics and higher.
-nN            Inverse, equivalent to: +hHeElL
SetList String. A list of set names, separated by commas. Sets are defined in Sets.txt