Some modules in GUDHI are MIT, others are GPL v.3 because of third-party dependencies.
More details on https://gudhi.inria.fr/licensing/

In Python you can easily know the license of a module by asking:

import gudhi
gudhi.alpha_complex.__license__   # Because of CGAL dependency
   'GPL v3'
gudhi.rips_complex.__license__    # No third-party dependency
