It was initially based on (forked from) the great libptp2 library by Mariusz Woloszyn but has since been moved over to follow Marcus Meissners and Hubert Figuere's libgphoto2 fork of libptp2 (or is libptp2 a fork of libgphoto?). The core implementation is identical to libgphoto2, there is just a different API adapted to portable media players.
It is of course licensed under the GNU Lesser General Public License.
On 2006-12-09 OSTG reporter Robin "Roblimo" Miller was given a Zune by marketer Tyler Welch during a visit to Microsoft. Roblimo writes:
The $250 (list price) Zune was too much. I wasn't going to take it at first. Then Microsoft marketer Tyler Welch told us what he really wanted was feedback, not just to give us a freebie; that he wanted us to let him know what we thought of the Zune and what we thought our readers would think of it. I piped up and said something along the lines of, "If it's going to be popular with my audience you'll see projects on SourceForge.net to either run Linux on the Zune or to use it with a Linux PC."
That Zune has now been passed to Richard Low of the libmtp project as a development target. We count this as official sponsoring and a signal to other device vendors to provide libmtp with reference hardware for interoperability tests with libmtp. Cudos to Microsoft for showing the way!