The mod_newmodule template does not include any licensing information on the template itself.
The files within it include the GPLv3 license, as Moodle usually does.

However, if someone bases their code on the template, their code is arguably a derivative work and must therefore be licensed compatibly with GPLv3.
Obviously this is not the intent of the template, and the license boilerplate in the various files is only meant to be a suggestion.

We really need to make this better/clearer. I'd suggest that we add to the README.md to state something along the lines of:

This template is licensed under Creative Commons.

Any license within the included template files are provided as an example only, and we advise you to choose your preferred license carefully before releasing your plugin.