wasnt the issue of the wesnoth downloader already decided in issue #1440 ?

in any case another similar issue came up since then, and as i remember the decision to make was whether to treat it like a third-party package manager, an issue that is still undecided

From https://forums.wesnoth.org/viewtopic.php?f=6&t=46093&p=618954:

The source code has to be GPL:

 All code (WML, Lua, etc) assets must remain under the existing GPL licensing. These updated changes only apply to music and art resources.

Music and art resources under CC licenses can also be used:

 You now have access to music or art resources from sources outside Wesnoth, as long as they are licensed under a CC license and you are allowed use of them.

So if I interpretate the Free System Distribution Guidelines correctly, the "Music and art resources" can be considered as "Non-functional Data".

About non-functional data:

 It can be included in a free system distribution as long as its license gives you permission to copy and redistribute, both for commercial and non-commercial purposes. For example, some game engines released under the GNU GPL have accompanying game information—a fictional world map, game graphics, and so on—released under such a verbatim-distribution license. This kind of data can be part of a free system distribution, even though its license does not qualify as free, because it is non-functional.

If I understand correctly, at the time of writing, all the Creative Commons licenses require the work to be redistributable.

However some licenses like the CC-NC and CC-ND don't allow to "copy and redistribute" for commercial purposes.

So the way to deal with this could be to first look if there are any art licensed under the CC-NC and CC-ND licenses. If there is none, it might be a good idea to try to convince upstream very diplomatically not to allow such licenses.

Given the violence of some of the prior exchanges with upstream, it would be best to prepare that before hand.

In the worst case it might be useful to make a wesnoth-libre, as most users (me included) would expect the free system distributions to take care of the "package managers bundled in software" when it is not obvious that it's the user responsibility to verify that the software being downloaded/installed respects the free software distributions guidelines.

Users using a browser to download a random tarball would not expects the distribution to check the tarball for them.

However some users (me included) assume that in-game add-on manager won't download nonfree addons, especially if we are not warned about it very very clearly.

I thinks that a we should develop either a standard alpm-hook for any packages that fall into this 'Third party package manager' category.
The hook could strongly warn the user that Parabola can not police TPPMs. And let them know that if they use the package the responsibility
theirs alone.

That or we create another Blacklist package "Your-package-freedom" and any of the TPPM can go on that list. We could incluse it in [base]
or have it as an optional install like your-privace or your-emulator...