Development Guide
Copy-Paste-Detector
Copy Paste Detector
The "phpcpd" target generates an xml-file that holds locations of duplicate code. Duplicate code violates the DRY-principle (Dont Repeat Yourself) and should be double checked if it's really really necessary.
Prerequisite is, that your build includes the "phpcpd" target, which writes a file build/logs/pmd-cpd.xml
This is the report you get, browsable: