In poky reference manual http://www.yoctoproject.org/docs/current/poky-ref-manual/poky-ref-manual.html, the descriptions for some core-image-XXX below are missing. /home/yocto-build5/poky/meta/recipes-rt/images/core-image-rt.bb /home/yocto-build5/poky/meta/recipes-rt/images/core-image-rt-sdk.bb /home/yocto-build5/poky/meta/recipes-graphics/images/core-image-gtk-directfb.bb
I added three descriptions for the missing core-images. You can view the commit at http://git.yoctoproject.org/cgit.cgi/yocto-docs/commit/?id=b83f9fa2a2de867ef9973b84aa1bec94e8071e45. You can also see the fix in http://www.yoctoproject.org/docs/latest/poky-ref-manual/poky-ref-manual.html.