It seems that Jack did some spying on you (the good spying, not the creepy spying) and the files are hidden around the area, so he wants you to find them before the Dahl guys do. Make your way to the first waypoint, which is in the trash area. Use the nearby mound of garbage to jump over the barrier, then break the lock on the bin and collect the ECHO.

For the second ECHO, it’s on a dead body that’s hanging above the area. To grab it, you can simply shoot the platform the body’s on and it will fall to the ground. The third ECHO is inside the store room where you got the Claptrap unit during Home Sweet Home to open up Jack’s office. It’s inside the locker.

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The last ECHO is located on top of the waterfall, but you can’t jump to it. Instead, find the switch along the wall to open a path that leads directly to it.

The last ECHO is a bit tricky to get to, as it’s hanging on a balcony above some water and you can’t grab it under normal circumstances. Facing the waterfall, go left and hug the wall until you come to a highlighted switch, which opens a door. Use this path to reach the ECHO, then return to the bounty board to finish the mission.