It’s a bit more complicated than that because MPL is itself a weak copyleft license that requires that the MPL licensed source code is always made available to recipients of a binary or derived work. The difference from GPL is that it does not require that all additional parts of the derived work are also licensed under MPL, (ie. not viral copyleft) meaning that the MPL licensed work can be linked with proprietary code without requiring that the proprietary code make its source available, but unlike BSD or MIT licenses it does not allow the MPL licensed code to be made proprietary.
The complication comes when linking MPL code with GPL code, even though MPL is GPL-compatible, since this requires that the entire derived work must now be made available under the GPL, while the original MPL licensed parts become dual-licensed under both MPL and GPL.
If Waterfox developers allowed this then it would prohibit the use of the whole derived work in proprietary projects (as they would now need to be GPL), so it would be removing rights that they have already given to downstream users of their code. Proprietary projects would therefore have to remove the GPL licensed additions (in this case it would be the UblockOrigin code) and link just the MPL licensed parts, which would mean using only part of the whole browser.
Personally I agree with you: I prefer GPL licensed projects. But MPL is not a bad license and I can understand and respect that some developers would make that choice (especially since the project is already licensed under MPL as it’s a fork of Firefox).
AFAIK MPL is viral, but only at the file level. In other words, if you modify an MPL-licensed file, your modifications need to be MPL-licensed, but if you add additional files, those can be a different license.
I think you misunderstood what “viral” mean in that context.
If a file, under GPL, is added to a project, the whole project becomes dual licensed under the original licence plus GPL, which propagate to the whole project, like a virus. I know comparing it to something like a virus sound derogative, but this is the best way to describe its effect.
If a file, under MPL, is added to a project, the project do not become MPL, only the added part is. Said project cannot change the MPL licensed part to another licence, but still can build anything it wish using it.
Globally, a GPL licensed project protects the user more, but also prevent the devs from doing a lot of thing, which MPL does not.
In the end, this is the devs freedom to chose which licence they wish to publish their code under, not ours.
It’s a bit more complicated than that because MPL is itself a weak copyleft license that requires that the MPL licensed source code is always made available to recipients of a binary or derived work. The difference from GPL is that it does not require that all additional parts of the derived work are also licensed under MPL, (ie. not viral copyleft) meaning that the MPL licensed work can be linked with proprietary code without requiring that the proprietary code make its source available, but unlike BSD or MIT licenses it does not allow the MPL licensed code to be made proprietary.
The complication comes when linking MPL code with GPL code, even though MPL is GPL-compatible, since this requires that the entire derived work must now be made available under the GPL, while the original MPL licensed parts become dual-licensed under both MPL and GPL.
If Waterfox developers allowed this then it would prohibit the use of the whole derived work in proprietary projects (as they would now need to be GPL), so it would be removing rights that they have already given to downstream users of their code. Proprietary projects would therefore have to remove the GPL licensed additions (in this case it would be the UblockOrigin code) and link just the MPL licensed parts, which would mean using only part of the whole browser.
Personally I agree with you: I prefer GPL licensed projects. But MPL is not a bad license and I can understand and respect that some developers would make that choice (especially since the project is already licensed under MPL as it’s a fork of Firefox).
AFAIK MPL is viral, but only at the file level. In other words, if you modify an MPL-licensed file, your modifications need to be MPL-licensed, but if you add additional files, those can be a different license.
(In practice, I suppose that that’s fairly weak?)
I think you misunderstood what “viral” mean in that context.
If a file, under GPL, is added to a project, the whole project becomes dual licensed under the original licence plus GPL, which propagate to the whole project, like a virus. I know comparing it to something like a virus sound derogative, but this is the best way to describe its effect.
If a file, under MPL, is added to a project, the project do not become MPL, only the added part is. Said project cannot change the MPL licensed part to another licence, but still can build anything it wish using it.
Globally, a GPL licensed project protects the user more, but also prevent the devs from doing a lot of thing, which MPL does not.
In the end, this is the devs freedom to chose which licence they wish to publish their code under, not ours.