Hadoop Fault Injection framework seems broken

I noticed a hidden documentation "Fault Injection Framework and Development Guide" (https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/FaultInjectFramework.html). This page is not linked by any other Hadoop/HDFS documentation.
Looking at the code, it was implemented in '09, and basically untouched since then. The build instruction no longer works, since Hadoop migrated from ant to Maven.

This seems to be a useful feature for testing, but no one seems to be using it.