So I found a citadel in wh space deanchoring, and managed to track it until it deanchored (I hacked the station and guessed from the reinforcement time they choose they’d also pick a deanchor time in the same hours - so I swung by to check the location around that time every day). I managed to witness deanchoring, unfortunately I didn’t have the firepower to take on the crew that was already there to scoop it up, so no go on snatching the citadel. But there was also a “Hanger Container” that spilled out when it deanchored.
It appears that I can’t do anything with this other than blow it up for tears? They’re bigger than (I think) any ship can scoop, and password locked. Is this something that all citadels do when they deanchor/blow up? Is this working as intended?