The following packages are in 5.6/updates/x86_64: firefox-3.6.14-4.el5.centos.i386.rpm firefox-3.6.14-4.el5.centos.x86_64.rpm xulrunner-1.9.2.14-4.el5.i386.rpm xulrunner-1.9.2.14-4.el5.x86_64.rpm xulrunner-devel-1.9.2.14-4.el5.x86_64.rpm xulrunner-devel-1.9.2.14-4.el5.i386.rpm

The following packages are in 5.6/updates/i386: firefox-3.6.14-4.el5.centos.i386.rpm xulrunner-1.9.2.14-4.el5.i386.rpm xulrunner-devel-1.9.2.14-4.el5.i386.rpm

The packages belong to CESA-2011:0310 which was never announced.