in the spec file it says : License: LGPLv2.1 - which obviously isn't right, since it's not a library.

https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
A "library" means a collection of software functions and/or data prepared so as to be conveniently linked with application programs (which use some of those functions and data) to form executables.

mbw is an executable (application program).

Thanks
-Robin