To find out which plugins are bundled with Jenkins, look in the WAR file for .hpi and .jpi files.
For example (v1.630).
% unzip -l jenkins.war | grep hpi 164546 09-20-15 12:03 WEB-INF/plugins/script-security.hpi 112483 09-20-15 12:03 WEB-INF/plugins/antisamy-markup-formatter.hpi 949638 09-20-15 12:03 WEB-INF/plugins/windows-slaves.hpi 64366 09-20-15 12:03 WEB-INF/plugins/ssh-slaves.hpi 74973 09-20-15 12:03 WEB-INF/plugins/ssh-credentials.hpi 38073 09-20-15 12:03 WEB-INF/plugins/javadoc.hpi 1030550 09-20-15 12:03 WEB-INF/plugins/pam-auth.hpi 929025 09-20-15 12:03 WEB-INF/plugins/cvs.hpi 55546 09-20-15 12:03 WEB-INF/plugins/external-monitor-job.hpi 50065 09-20-15 12:03 WEB-INF/plugins/translation.hpi 128645 09-20-15 12:03 WEB-INF/plugins/mailer.hpi 101895 09-20-15 12:03 WEB-INF/plugins/ldap.hpi 90421 09-20-15 12:03 WEB-INF/plugins/ant.hpi 331127 09-20-15 12:03 WEB-INF/plugins/junit.hpi 238601 09-20-15 12:03 WEB-INF/plugins/matrix-project.hpi 10805330 09-20-15 12:03 WEB-INF/plugins/maven-plugin.hpi 4683101 09-20-15 12:03 WEB-INF/plugins/subversion.hpi 406478 09-20-15 12:03 WEB-INF/plugins/credentials.hpi 79681 09-20-15 12:03 WEB-INF/plugins/matrix-auth.hpi