This unnamed quest can be completed by exploring the territory of the Small Zone in S.T.A.L.K.E.R. 2: Heart of Chornobyl. Here you will meet a free stalker who needs help. We tell you how to help the guy, what choices to make, and get all available rewards.
To start this unnamed quest, head to the northeastern part of the Small Zone. Here on the map, you can see a question mark if you have not previously visited this area. Approaching the anomaly, you will hear a male voice — the stalker will ask for help with a certain task.
Talk to him and agree to help. Completing the task is quite simple. To do this, you need to climb into the anomaly and retrieve the body of the second stalker. For this, you can throw bolts in front of you to find a safe path or clear the way.
Once you reach the body, take the PDA, but do not rush to inspect his pockets. If you do this, you will lose 800 credits. But only in this way can you get a good artifact without a fight. If you carry the body out of the anomaly, you will get the money. However, as soon as you try to loot the dead stalker, you will be attacked by Yurko.
How to proceed is up to each player individually. Considering that with proper help, Yurko promises to help the hero in the future, this might play a role. But we like quick profit, so we kill the stalker, loot the artifact, and leave. Of course, this is a joke. We will update the guide if Yurok really decides to help Skif someday.
I should elaborate. I tried this again and it didn’t work. To make it work you have to pick him up from out of Yurko’s sightlines (which requires you to place the body behind him in the first place) and you have to trigger the ‘show some respect’ sentence by clicking ‘talk’ on Yurko. Once he’s talking, quickly pick up the body and he won’t notice. Then proceed to put the body behind the car and loot him without aggro-ing Yurko. Again, disclosure: no idea if this still counts as betraying him in the games code.
If you bring the body to him, have a drink to pay respects, befriend him, you can still get the loot without aggro-ing him. All you have to do is pick the body back up out of his line of sight, then drop the body behind the nearby car. I looted him, and double checked that we were still cool afterwards. It worked, at least at a face-level because he talks to me like normal. No idea if this has affected something down the road with him though.