`error: undefined variable 'license'` with any open-vsx extension

[SuperSamus]

When trying to build any extension from open-vsx:

error: undefined variable 'license'

       at /nix/store/9r1xp2rj6zazr07z8i304fsjbvwcd1k9-source/flake.nix:41:42:

           40|                     inherit changelog downloadPage homepage;
           41|                     license = licenses.${license};
             |                                          ^
           42|                   };