All Xmipp code and plugins, are licensed under the GPL3 License.
Now, Xmipp interacts, and in some cases installs 3rd party software with its own license that must be observed.
So, it is under the user’s responsibility to check the license of each software Xmipp is installing.
In most cases, if not all, software is freely available for academic use and industry but there are few exceptions where industry users, or in some extreme cases even academic ones, are not granted free usage. You must check in each case.