While it's perfectly fine to have a declaration like this:

<properties>
  <clover.licenseLocation>clover.license</clover.licenseLocation>
</properties>

and next refer it in maven-clover2-plugin's configuration like this:

<configuration>
   <licenseLocation>${clover.licenseLocation}</licenseLocation>
</configuration>

it's misleading for users, because in case they would like to pass it via -D parameter or declare in settings.xml without having the <licenseLocation> in maven-clover2-plugin section, it will not work, because the correct property name is 'maven.clover.licenseLocation'. See:

https://docs.atlassian.com/maven-clover2-plugin/latest/setup-mojo.html#licenseLocation

Correct all references in documentation on confluence.atlassian.com, answers.atlassian.com, maven-clover2-plugin source code, tutorial source code.