If you get the “Check out the Cage” Side Quest, it drops a loot Pack.
It can range from Common to Epic (as far as I’m aware)… but the thing is, it sonetimes doesn’t Display it right.
One Time I got a Epic Loot Pack there but it didn’t show an Epic Loot Pack under the cage… just randomly said Epic Loot Pack aquired.
To be honest… I have NEVER seen an in game drop of the Epic Loot Pack, neither in the Big Chests which always have gear nor at this spot.
Anyway… if you wondered there you got a Pack from, this might be the spot.