Can an enslaved worker be liberated? In other words, if an enslaved worker is captured by a civilization other than the one that enslaved it, does it retain the same graphics? And are there any special conditions for that? Like does it have to be the civilization from which the original unit was enslaved?

Every worker has a Nationality tag...so I guess that if you take back your stolen worker, it will become normal again.

Of course, I may be wrong. This is just a guess.

And I do not see how taking an already-stolen worker will return it to "non-stolen" status.

If you take an enslaved worker it will be a normal worker only if it has your nationality. Otherwise it is just a normal enslaved worker.

Hmm... well, that sort of leaves me back at square one... and also means I'm going to have some extra work to do.