The maven configuration mentioned in the Usage section of the Natural Docs Maven Plugin site:
<groupId>org.codehaus.mojo.naturaldocs</groupId>
<artifactId>naturaldocs-maven-plugin</artifactId>
<version>1.0-SNAPSHOT</version>
However; I can’t seem to find any version in any Maven repository including Maven Central or the Snapshot repo.
I was able to find what seems like the initial version attached to this Mojo plugin submission but it only includes source, and while it’s nice to look at I don’t wish to compile it for use myself.
Grab the source archive that you referenced and unzip it in a convenient spot.
From that folder, run:
Assuming that runs without issue, run:
Assuming that runs fine, check the local deploy works as expected by including the pom reference in your project.
If your project build without issue, then deploy it to your local Maven repo by running:
Or have one of your local Maven admins deploy the pom and jar manually.
I hope that helps.