Hullo greensleeves,

Don't worry; the package is free.

Tissevert 写道：
> From Ethan Schoonover's original repository[1] it seems to be 
> the MIT license but
>
> - I can't find it in guix/license.scm, is that even an 
> admissible free license ?

Yes.  It's available as ‘expat’.  See the third paragraph of [0].

> - The existing emacs-solarized-theme[2] package shipped with 
> guix is distributed
>   under a gpl3 license ?! (how is that possible ? can one 
>   redistribute software
>   under a different license than its original one ?

Yes, you can combine (say) MIT/Expat-licenced software with (say) 
GPL-3 software and redistribute the combination as (say) GPL-3. 
You can also add your own or others' GPL-3 code to existing Expat 
software.  The modified result is GPL-3.

In both cases, the original Expat software doesn't go away, but at 
least people can't use the GPL-3 portions to restrict others' 
freedom.

Kind regards,

T G-R

[0]: 
https://en.wikipedia.org/wiki/MIT_License#Minor_ambiguity_and_variants