pcl_openni_face_detector1
Pcl_* tool that do something interesting with a pointcloud
Part of pcl_pointclouds(1).
Overview
The program that you are asked for a man page, has no man page. However, it doesn't means that there's no information about it. You can install the libpcl-doc package or check:
http://pointclouds.org/documentation/
Releases
Unchanged in 3 releases since Debian 9 (Stretch).