Yes, do not look at me with that face, all the themes and plugins for WordPress are licensed GPL . I have recently read two posts that point in this regard, about the interesting implications of the fact that WordPress uses the GPL license . And is that GPL involves many aspects of freedom of dissemination and free also, in which perhaps the developers of plugins and themes of payment have not repaired. They do not seem to have realized what a GPL license matters when you develop for a particular platform that uses that license.
And the implication of the GPL license is clear : all the plugins and themes for WordPress automatically fall under the GPL license. In other words, even if you paid for an advanced plugin or premium theme, and although the author has tried to add another license, just for the fact that they are designed for use in WordPress you are free to modify them, give them away for free or even resell them if you want .
This is because of this particular paragraph of the GPL license :
You must cause any work that you distribute or publish, that in whole or in part It contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
And then in the License FAQ aims that …
f the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug -ins. This means the plug-ins must be released under the GPL or a GPL-compatible free software license, and that the terms of the GPL must be followed when those plug-ins are distributed.
This means that at the moment a theme or plugin uses a single function of WordPress code, the GPL license to which this CMS is hosted automatically absorbs it. And as the plugins and themes must use WordPress functions to work automatically they enter the GPL license .
What does this mean?
Well something as simple as that you can delete the theme links that the author of it forbids you to withdraw (even in the sponsored themes). Moreover, although the author tries to use a Creative Commons license for the theme, and asks you to respect the links, you do not have to because you are the one who is violating the GPL license by placing a CC license.
And for the plugins it is exactly the same. In fact, it is the same for any type of software or development based on WordPress. And the GPL license allows you to do what you want with that software, even resell it.
If you realize, GNU licenses are like a virus, they extend to any software that you touch, one of the reasons why Microsoft He has shunned them like cancer in all his developments, because he imagines that one day they use software with a GPL license in some product that uses the Windows source code, from that moment the operating system would also be GPL.
Interesting do not you think ?. I do not know what this will look like to developers of paid plugins and themes, but folks, that's what it is. Richard Stallman must be happy with this kind of thing and the pseudo-Marxist philosophy of the FSF that he expands where he can, even in schools .
] What do you think ?, Did you notice this issue?