How buildRetention works?

[vleungcrypto]

The buildRetention object is:

"buildRetention" : { // Build retention information
"deleteBuildArtifacts" : true, // Automatically remove build artifacts stored in Artifactory (true/false)
"count" : 100, // The maximum number of builds to store in Artifactory.
"minimumBuildDate" : 1407345768020, // Earliest build date to store in Artifactory
"buildNumbersNotToBeDiscarded" : [ ] // List of build numbers that should not be removed from Artifactory
},

Q1: Is there any REST api or JFrog cli that can retrieve the buildNumbersNotToBeDiscarded and other buildRetention properties from a project?
Q2: If in myProject (release build, build number 10), we set buildNumbersNotToBeDiscarded to be [ "10" ]. Then in my up coming release build (say build number 20). Should I set the buildNumbersNotToBeDiscarded to be [ "10", "20" ]?
Q3: Can count set to be unlimited, is -1 means unlimited?
Q4: If in myProject build #10, we set count = 200, then in build #20, we set count = 500. Does it means the Artifactory will store 500 builds?
Q5: Any wiki page provide more info about buildRetention?

Thanks.