If you forked from really old leaked source, explain how you got the AI which I coded, and the airlock hacking which I coded, and the pipes, power, and so on which were added by hobnob in 2007-early 2008 or so (IIRC - the svn history on the sourceforge openss13 repository doesn't go back before april 2008, and they were done before that), and all the other things which weren't in the leaked source. (And even if someone managed to pull off a miraculous copypasta/merging job, all of that should have been infected by LGPL licensing because they were either from openss13 or were code which was forked from openss13).
My pre-merge code doesn't seem to have a license file in it, which, if you are also lacking one, would explain why. However, that doesn't mean it isn't subject to a license, because the code it was forked to DID have a license file in it. It was only missing due to an oversight (I missed the file at some point in the process of preparing the forked version - don't ask me why, it's sitting in /trunk in my non-updated openss13 folder, although it's named lgpl-3.0.txt instead of LICENSE for some reason... which might be why, actually, it's rather non-attention-getting). There has been an lgpl-3.0.txt file in the openss13 trunk since april 6 2008, the first revision on their sourceforge svn, when it was imported from some other repository on ss13.net (I can't see back before then, since the previous repository no longer exists). My first changes were on 3/26/2008, presumably based on either the other svn repository or a download (I don't remember), and my last released version before merging with openss13 was on april 29 2008.
More likely (as others have stated, and as what I've seen in the station suggests) you forked the goons' version (I won't try to guess what version of it), which already had the AI etc, due to having been forked from an intermediate version of my version from 2008 (not the april 29th version, an earlier one), according to a statement from one of the developers of it in 2008 - although since it has all the stuff I made it up to a certain point it would have to be fairly obvious
. Well, obvious to me, anyways. I could probably find the cutoff point by looking up when I implemented round explosions, which you are missing.
In any event, even if you did fork off some other version, any version which has the AI in it, which is basically every version of SS13 in existence now, would have to be (a) forked from my version, which came from openss13 (the license file being missing when I packaged it up was due to it being overlooked, as I've said), or (b) from the merged openss13 after I merged my version back into it (which does have the license file in it, though I think everyone used one or another version of the goons' fork), or (c) copied the code for the AI, airlock hacking, and whatever else, out of some other version, which means it's subject to the licensing conditions covering that code. That would be the LGPL still.