I noticed that BIP-0039 does not specify a license.
This PR adds a CC0 1.0 license to BIP-0039. I think CC0 is appropriate in this case, given that there is no code in this BIP. But I’m not an expert.
I think, as a matter of practicality, the word lists should also be covered by this CC0 license as well. I’ve attempted to explain that in my edit, though I am not a lawyer and welcome edits/suggestions.