Git rev: master/36feb38045b7a2af86ece147fec54b0db3bf491f Currently the build appliance image doesn't contain the source code in downloads directory. So when build an image in BA, it should fetch the source code first. This will increase the build time. In previous BA image (using HOB), the source code is in the BA image. So now it's better to add the source code in BA image also.
This was made configurable in http://git.yoctoproject.org/cgit.cgi/poky/commit/?id=09eab6b992c9ef1885ccfd6740c95b66df7c2809 so was a change to make the BA image more manageable. It can still be turned on if needed.
The variable that you need to modify is BA_INCLUDE_SOURCES. A user specified non-zero value will result in the build appliance image to also contain sources. By default the sources are not loaded, to keep the Build Appliance image small.