As I pointed out then, the solution to this is very simple: regardless of whether you want to place restrictions on how your OXP is used or want it to be used without restriction; regardless of how obvious you think this is – you must specify a license when you release an OXP, or any other work. This is not optional.
If you don’t, people cannot know how they’re allowed to use the work, and in what context. Any use – including downloading it and using it in Oolite – is somewhere between “legally murky” and “illegal”. In practical terms, people will have to guess what your intentions are. When you find out, three months or three years later, that someone’s guessed wrong, nastiness ensues.
You should not try to craft licensing terms yourself, because they are likely to be vague and invalid. This includes statements like “anyone can do whatever they want” or “this is in the public domain”. In most countries, you cannot legally give your work away with no restrictions.
- If your OXP contains models, textures or scripts wholly or primarily copied from Oolite, it must be distributed under the GNU General Public License version 2 or later, the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license or both. Of these, the CC license is more appropriate for OXPs. If you’re not sure whether your OXP falls under this requirement, ask.
- If your OXP copies data or designs from other sources, the licensing requirements are up to that source.
- If you upload your OXP to EliteWiki (not just if you have a page about it there), you agree in the process of uploading to license it under the GNU Free Documentation License version 1.2. (This is an awful license for an OXP and a pretty bad one for a wiki, but that’s the way EliteWiki is configured, and it can’t be changed without getting the permission of everyone who’s ever contributed to the wiki or rewriting the MediaWiki software.)
- If you want an absolute minimum of restrictions, as close to “giving it away” as possible, I suggest the CC0 waiver. Note that this permanently waives all control and right of attribution. Don’t take it lightly.
- Otherwise, I suggest the Creative Commons license chooser. There are many other existing licenses you might want to consider, though.
Note that a license that permits derivative works also allows someone else to pick up your OXP and maintain it should you disappear from the Oolite community at some point in future. It’s been known to happen.