BugsInPy itself has no license information. Therefore, it is unclear under which condition it is allowed to use it.
I am not a lawyer. So, all things mentioned here are only my personal opinions on this topic.
Permission from all contributors
Adding a license to an existing project normally needs the permission from all contributors (c.f. StackExchange), at least if the contribution of the person is copyrightable. Very primitive changes are normally not copyrightable (e.g., #93).
To get the permission from every contributor for a license, first a suitable open source license have to be chosen. As BugsInPy was introduced as kind of counterpart to Defects4J, using the same license (MIT) would be an option. The (main) contributors may should suggest preferred licenses (with / without copyleft). (My personal favorite permissive license is the quite new Blue Oak Model License 1.0.0)
License of patches
If I understand correctly, the patches for the bugs are from the respective projects themselves. Therefore, the copyright is by the respective authors / projects and the license of the respective project applies to the patch files. To annotate this different license and copyright holder, I would suggest to use REUSE for the whole BugsinPy project.
BugsInPy itself has no license information. Therefore, it is unclear under which condition it is allowed to use it.
I am not a lawyer. So, all things mentioned here are only my personal opinions on this topic.
Permission from all contributors
Adding a license to an existing project normally needs the permission from all contributors (c.f. StackExchange), at least if the contribution of the person is copyrightable. Very primitive changes are normally not copyrightable (e.g., #93).
To get the permission from every contributor for a license, first a suitable open source license have to be chosen. As BugsInPy was introduced as kind of counterpart to Defects4J, using the same license (MIT) would be an option. The (main) contributors may should suggest preferred licenses (with / without copyleft). (My personal favorite permissive license is the quite new Blue Oak Model License 1.0.0)
License of patches
If I understand correctly, the patches for the bugs are from the respective projects themselves. Therefore, the copyright is by the respective authors / projects and the license of the respective project applies to the patch files. To annotate this different license and copyright holder, I would suggest to use REUSE for the whole BugsinPy project.