Should an addon be licensed under GPL or proprietary license?

According to GNU GPL, any modifications to a software licensed under GPL should also be licensed as GPL by virtue of the license “viral” nature.

Question: Is an addon a modification of Anki or is it an independent work that can have proprietary license?

According to the Terms and Conditions page:

As add-ons extend the computer version, they must be licensed under the AGPL3 or a compatible license. If you do not explicitly state a license, it will be assumed to be AGPL3.


Ok. Any opinion with what’s going on with Anki and AMBOSS? How does it affect the licensing of the latter as Anki is under AGPL3?

I don’t have a definite answer as I’m not knowledgeable about licensing, but I think AMBOSS is in the clear as its source is available?

Maybe this touches on the same topic that was raised on the reddit earlier, about the new AnkiHub plugin.

In that case I assume they’re in the clear because the add-on itself should be freely available but you require a subscription to use the collaborative deck features.

But doesn’t AGPLv3 explicitly cover servers?

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AFAIK, AGPL was intended to prevent people from modifying open source code, hosting it on a server, and failing to provide the modifications to others. That’s not what’s happening here - assuming the add-ons are being released under a compatible license, I do not believe they are breaking the license by making network connections to proprietary services.


BTW, I’m working on some minor modifications to the AMBOSS add-on and found out that the JS files are minified/obfuscated. I think this is against the AGPL if the original un-obfuscated files are not made available (I don’t think they currently are)?


IANAL, but my understanding is that they should be providing the original source.


Sorry to revive an old thread, but did you ever figure out how to make modifications to the addons code?

I only made minor modifications like disabling the tooltips inside content matching certain CSS selectors. At the time, I was mainly interested in figuring out how the add-on highlights words that span across multiple elements (like partially bolded words). It turns out it uses mark.js.
If you plan to make major modifications, maybe try your luck with some JavaScript deobfuscator/unuglifier first.

I actually emailed AMBOSS about publishing the full sources but got no reply. Maybe @glutanimate can help.