jenkinsci/cvs-plugin — pull request #20 by ndeloof (2013-04-04 16:25:09+00:00)
Title: FIXED JENKINS-17470 uncheck "Show all CVS Output" has no effect

I've used wireshark to compare protocol frame for command line cvs -Q update vs jenkins plugin with veryQuiet set. command line do set both Global Options -q and -Q. Seems cvs server ignore -Q if -q is not set, not sure this is documented by CVS spec, but this is the actual behavior.