Which maven repository (.m2 or /business-central/maven2/) is used at runtime by BPMS/BRMS 6 and RHDM/RHPAM 7?

Issue

I develop my kjar outside of business-central console.I use maven to build and deploy my projects. I used to think that it is necessary to mvn deploy my kjar project to BPM Suite's 'guvnor' maven-repo (e.g. http://localhost:8080/business-central/maven2/) before I could use BPM Suite's various REST api's to operate kjars. But then I learned that I only have to mvn install my kjar project, which installs it to my local maven repo. I learned that, at runtime, /kie-server and /business-central depends on my local maven repository (e.g. ~/.m2/repository) and not the 'guvnor' repository. What is the purpose of the guvnor maven repository ? Why and when would I want to deploy stuff there?