https://portableapps.com/apps/games/sauerbraten_portable says "App License: Open Source (ZLIB, Assets: CC)"
but http://sauerbraten.org/README.html#license says "The game is freeware [...] If you want to produce new content with the Cube 2 Engine, you have to be aware that the source code may be Open Source, but the game and the media it consist of have their individual licenses and copyrights. [...] In this sense Cube 2: Sauerbraten is similar to games like Quake (its code is Open Source, but its media is not)."
Please double-check my work, and if you find that I'm correct, you may wish to adjust the info on your website and add the Freeware tag to the app. Alternatively, I suppose you could strip the non-libre assets from your release.
I think you are correct. I've updated the page to indicate this. I thought the assets were Creative Commons back when I packaged it in 2011. The page has been updated to properly reflect the license the project indicates.
I think we're ok with packaging as they allow packaging for different platforms, but I've contacted the publishers to be sure. I hope we can continue to make it available for folks.
Sometimes, the impossible can become possible, if you're awesome!
I got a note back from "Aardappel" and he confirmed that our package fits into the "You may re-compress using different archival formats suitable for your OS" exception in the license and thanked us for maintaining it.
Sometimes, the impossible can become possible, if you're awesome!