Where is this unnoticed stash?

[icommandtheekneel]

In the poppy field there's an unnoticed stash that I can't locate.

The description reads "F*** this! I'm dropping it here"

I search the house high and low but can't find anything.

[Maniac]

Im not sure anymore if thats the same but i had one i searched for ages until i found out its on the side of the roof, you cant get in there but there is a little hole where you can grab the backpack from

[RoverUKSF]

It`s behind the board in Ahroprom underground (X5 Lab). You`ll be there during In Search of Past Glory main guest. The room with the board is accesible through Ladder in one of the open concrete shafts.