That type of cable is usually pretty tight. I usually wiggle them out slowly. And of course undo the tape if you haven't already.

the clamp may be a small element just on the edge of that socket - i dont see these personally without glasses; so maybe inspect the socket some more, its obscured here;

If no plastic lockers there, just take it out slow and don't worry about.

It's confusing. I don't think there is a clamp but the service manual suggests there is.

I've taken some photos with a phone instead of a potato and I don't see any edges. I also tried to poke around with some tweezers but nothing seemed to move. Still didn't get the cable out but I guess I'll just keep trying by wiggling it.

I wonder if there really is a lock and the tabs are just broken off

Hmm, now that you mention it, the surface does seem a bit rough on the sides.

Except for the missing hard drive (and the bent pins...) I didn't see any hint that it was opened before. But I'll see if the 'pillar' in the middle can move because that could have been part of the clamp I guess.

speaking of rough, those pins don't look particularily shiny, maybe there's some corrosion preventing it from slipping out easily... did you try some contact cleaner as "lube" maybe?

I got it out. I couldn't find any moving parts so I just tugged on it on several occasions and it suddenly moved. There was no indication that it was getting loose, it just popped out. I will put some contact spray into the connector before I assemble it again.

Thanks for all the replies 😀