But that is not how it works, apparently. Regardless of the flag setting the units die if no facility with 'prisonType: 0' exists:
If everything is right, you get a live alien item.
If anything is wrong, you get a corpse item.
Hence my question regarding the proper way to define a recoverable alien unit/item that does not require a prison type.
All recoverable units need a liveAlien flag and optionally a prisonType (defaults to 0 if not defined).
Same as in OXC.
There is no such thing as "without a prison type"... that's simply not a thing.
Ask differently if you think I didn't understand the question... but the only answer to "can I have an item without a prison type" is "does not compute".
If you want to recover something completely else than a unit, there are (several) other ways how to do it.