Please clarify GPL license versions

[mgorny]

Currently, the AUTHORS file lists that a few of the icon sets were licensed "GPL":

https://github.com/shimmerproject/elementary-xfce/blob/1080fd5cd538102d369527b131d994c804b0d30e/AUTHORS#L21..L32

Could you, please, clarify which GPL versions are these?

[newhoa]

First, thanks so much for your work on Gentoo and FLOSS in general! And thanks for keeping this package available and updated and keeping an eye on the licensing stuff.

Short answer is GPL 2. But I looked more into it so here's more info! Looking back at the commit histories, those lines were in the initial fork in 2012 (and originated upstream in 2009).

At the time elementary-xfce was forked...

Gnome Icon Theme

Was GPL 2.0 (files inside Gnome Icon Theme 2.30 mention GPL 2.0 or later). 2.91, the dev release between 2.30 and 3.0 series, relicensed to a LGPL 3 and CC-BY-SA 3.0 dual license (LGPL3 is GPL3 compatible).

Humanity

Was GPL 2.0. Humanity and elementary are intertwined as I believe Danielle Foré was the creator or co-creator of both and the author of many (or maybe most or more?) of the Humanity icons. It seems Humanity did pulls from elementary. elementary went GPL3 in 2013 and it seems Humanity continued pulls. So while Humanity does not mention "or later" in regard to its GPL 2.0 license, these actions seem to imply it.

As for Tango... I don't think there are any Tango-related icons left in the theme. Even if so, the public domain content would have been relicensed to GPL 2.0 when incorporated. Edit: Public Domain content would still need to be identified according to FSF, but again I don't think any Tango content remains here so I don't think we need to worry about that. Just wanted to add the correction/info here.

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So originally all of these would have been GPL 2.0. Many have relicensed, but all of those new licenses are GPL 3 compatible. So I think relicensing elementary-xfce to GPL3 would be best. It would kind of re-unify all of these to a single license and I believe remove the need for listing all of these various licenses (please someone correct me if this is wrong). If we redo the AUTHORS file and go GPL 3, it would probably be best to keep these themes listed as origins/credits and not list a license since they would all be GPL 3 unified.

Any feedback from anyone on this analysis would be appreciated. I'd like to make sure everything is covered and taken care of correctly if we do relicense to GPL3.

[mgorny]

Thanks. I don't consider myself a licensing expert but I suppose you're correct, provided that all the original GPL 2 code was either relicensed to GPL 3 or originally had an "or later" clause.