@Caramdir Certainly I would consider my answer more as part of a "technique" than actual code that I would even think to lay claim on. It's not particularly generalizable in a way that would be useful in a package, I think (unless simply setting up some commands to draw the links rather than have them drawn using tikz syntax would be helpful to some.) Anyway, I'm with Andrew: blanket relicense to LPPL anything I post here.

I've added a paragraph saying that my code is available under both GPL and LPPL: see the wording at tex.stackexchange.com/users/175/charles-stewart. It's almost certainly problematic, and the Apache license would be less issue-ridden than the GPL, it occurs to me, but it is a starting point. Not that I posted any code worth packaging, mind you.

@CharlesStewart That looks reasonable. I presume that the copyright notice could and links and so forth could go in the package code. What do people think about having a question on meta that could be signed by whoever wanted to? Putting it in user statements is good, but having it on meta is more public and will encourage others to do likewise.

@AndrewStacey User biographies are changeable without recording the history, so Meta would be better.

I've taken the template from Charles' user statement. I think that the last part of his statement is there as clarification (namely the stuff about attribution and about the cc-wiki license). Looking at the LPPL, it seems that the attribution stuff is required. If anyone has a better blanket statement, please amend the question (but I'm not going to ask for it to be made CW as the answers most definitely should not be CW).