Silver Leggings (Outland Proper)

Object 'leggings silver githyanki gith' type armor, extra flags magic nolocate.
Weight 10, value 8928, level 126.
Object Quality (500 / 500 hps)
Armor class is 26.
 Modifies damage roll by 2 continuous.
 Modifies hit roll by 2 continuous.
 Modifies armor class by -30 continuous

There is a down exit from Outland Proper that leads to a hallway and some rooms. The silver leggings are on one of these mobs.

There are more than one kind. Here's another:

 Object 'leggings silver githyanki gith lordgear' type armor, extra flags magic nolocate.
 Weight 10, value 10571, level 125.
 Object Quality (500 / 500 hps)
 Armor class is 26.
  Modifies hp by 100 continuous
  Modifies damage roll by 2 continuous
  Modifies hit roll by 2 continuous
  Modifies armor class by -30 continuous

There's another that's worn by the Gith Commander, it can be found here.