From the changelog from version 1.06a (released 1st of July, 2011): "Added stealth= attribute to stations"
Testing on 1.7a1, the stealth attribute appears to be nonfunctional. While it looks like no one's ever used it in the intervening 5 years, this would be an invaluable addition for building adventures and spicing up vanilla content. (EDIT: It does work, but had issues for content)
With the modern systems, this would almost certainly require a full reimplementation to account for things like detection radius when mapping, behaviour around the Explorer auton, etc.
EDIT: PM explained it in IRC. Seems to work more or less as intended still, but might be worth expanding the mechanic eg: Making the military map not scan stealth stations. Seems it only works in certain ways and not others.
Special thanks to Digdug on this one. Without his excellent omnibus edition of the game changelog, I wouldn't have discovered that this feature used to be in the game.
This is probably the oldest regression/bug/tragically dead feature I've ever found. ^_^
I didn’t even know that stealth on stations was a thing at all, let alone a broken thing. o.o
Seriously though, yeah, there is all kinds of potential for this, like having hidden outlaw stations actually be hidden. Of course, another issue there would be for ships docked at said stations; if you can plainly see them around the station, it’s… still not particularly stealthy…
I think that works though as a hint that maybe there's something interesting out there. It should prevent mapping at a distance, so you'd need to get reasonably close to find a "hidden" base.
...also incentivises more use of stealth on NPC ships ^_^
It was that last bit that I was specifically hinting at. ^.~
…Also, making that something that can be modified with objSetProperty would be groovy…
Resolved myself. Turns out it does work, just not in the way that I thought. :)