Blind Grenades

Codex: Grey Knights on page 60 says that Blind Grenades are listed in the core rule book. Blind Grenades don't seem to exist in the core rule book in either 6th or the mini rule book in 5th.

Am I just blind, or did Blind Grenades simply cease to be in 6th Ed?

Aren't they just assault grenades?

That's the thing, I can't find anything on them outside of a random forum post elsewhere that calls them "defensive grenades that grant stealth against short ranged shooting". If it's that one, then how "short ranged" is "short ranged shooting"? I can't find nothin' on them.

if you read the entry in your codex again, you'll see these are defensive grenades.

pg 62, BRB, Defensive Grenades:
a unit with this type has the Stealth Rule WHEN: 1) they're within 8" of the unit shooting them, AND 2) they have not gone to ground.
models charging a unit with this type do not gain a bonus attack for charging, UNLESS, the unit is already in assault, or has gone to ground.