Cobbler deploys a yaboot binary over TFTP to enable network booting of PowerPC machines. Yaboot is GPL and is being distributed in binary form persuant to this section of the GPL license: c) Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) Source code to yaboot is available on http://yaboot.ozlabs.org. A full copy of the GPL is available in "COPYING".