In this case, the SDK is referring to a specific CD that was distributed with a development environment. I forget the exact name of the CD, I know I have one sitting in storage.
Anyhow, it contained the specifications for how the Amiga CD filesystem was to be layed out to be bootable. A variation of the ISO9660/Rock Ridge boot, IIRC. Basically, the files required are all the same stuff you need to boot an Amiga up from an HD (s:startup-sequence, the c: dir and tools, etc.). The custom part is in how you burn the CD.
