Please provide some information (few sentences) on what is process controller about and what is it for. We do have used the term process controller in configuration guide but there is no information what is his function in the whole domain environment.

I searched the WFLY documentation and I didn't find any info on this either.
The only article on net where I got some thing about it is stackoverflow answer here
http://stackoverflow.com/questions/30048157/wildfly-and-process-controller

I think our documentation should contain such info especially when configuration guide uses that term and order user to configure it in case.