Hi there,

I recently used a mod hosted on GitHub (https://github.com/DanWaLes/Warzone) and edited the code so it now does something else. (I wasn't sufficiently familiar with lua and Warzone API to develop a mod from scratch.) The new code is ~80% identical to the previous mod's code. I don't know how to contact the original developer. Am I allowed to post my code to GitHub and create a multiplayer game or does the original developer have some sort of copyright?

Warzone's terms of service state that all mods must use the MIT license. The MIT license is a very permissible one which basically says you can copy it and use it for whatever you like. Therefore, yes, it's OK for you to modify other's mods.

EDIT: see https://law.stackexchange.com/questions/74896

While DanWL has licensed his mods now under the MIT license, for future cases we can't extend the MIT license presumed by TOS Section XIV to usage by parties other than Warzone and the original author.

Concretely, if you're referencing this in the future:
1. You CANNOT assume that someone's mod is MIT licensed just because it was uploaded to Warzone. The Terms of Service are an agreement between Warzone and the uploader, not between the uploader and you.
2. You SHOULD obtain a license from the uploader, ideally by asking them to explicitly MIT license their software.

The original response below is at least partly incorrect, as is the entirety of Fizzer's response above.

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The mod itself is not explicitly licensed but pursuant to the Warzone Terms of Service (https://www.warzone.com/TermsOfService), the mod is presumed to be MIT licensed:

XIV. Mods

All mods uploaded into Warzone must be licensed with the MIT license. Any mods without a license specified are assumed to be licensed by the MIT license.

The MIT license grants you permission to:

...use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so...

(https://mit-license.org/)

Under the Warzone TOS, you should be good to upload the mod to Warzone (also under the MIT license). If you want to cover yourself, you can:
1) Contact DanWL- he's inactive on Warzone (https://www.warzone.com/Profile?p=9522268564) but you can still reach him on Discord (DanWL#2759) and ask for any explicit permission you might need (you don't need any)
2) Add a copy of the MIT license to your own code if you open-source it (you can copy and paste the contents of https://mit-license.org/ into a file called LICENSE at your root directory)
3) Ask DanWL to explicitly MIT license his code to avoid further confusion; under the Warzone TOS he's implicitly MIT-licensed any mods he's uploaded onto Warzone, but having an explicit LICENSE file adds clarity

Practically, there's no risk here for you to worry about. Since neither you nor DanWL are profiting in any way from Warzone mods, there's nothing to be gained from pursuing an infringement claim even if one exists.

EDIT: I contacted DanWL for you, so scratch #3


Edited 11/27/2021 18:30:15

Looks like DanWL: https://www.warzone.com/Profile?p=9522268564

No license means that the writer keeps all his rights, so especially forking the code and publishing it on your own repository is technically not allowed.


Edit: Scratch what I wrote above.

Edited 11/27/2021 00:11:39

Thanks, I should have looked up the ToS I guess!

EDIT: Norman was entirely right. See https://law.stackexchange.com/questions/74896/

Answer below is preserved for reference but is not legally correct.

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No license means that the writer keeps all his rights, so especially forking the code and publishing it on your own repository is technically not allowed.

+1 in general. The default state of source-available code is copyrighted and unlicensed.

However, in this case, Warzone TOS presume the MIT license for all mods, so at least as far as uploading to Warzone is considered from Warzone's perspective, anyone can do with DanWL's code as they wish so long as they accept the terms of the MIT license (basically "do whatever you want, but the author makes no guarantees and if something goes wrong it's not their fault").

Two updates:
1. DanWL has added the MIT license to that repository explicitly, so you're 100% safe

2. I'm curious about how much effect that Terms of Service clause has, so I asked on the Law StackExchange if anyone else is similarly curious: https://law.stackexchange.com/questions/74896/

Edited 11/27/2021 18:31:47

In case anyone is interested, my multiplayer game with the new mod is up: https://www.warzone.com/MultiPlayer?GameID=29153624