A GDP "spin" is an image based on the Genivi Development Platform that incorporates user experience code that wouldn't be brought into GENIVI Master for one reason or another.
GDP Spins are GDP-variations that are endorsed* by GENIVI, but primarily developed by separate teams or companies.
Spins differ from GDP Master by demonstrating a unique HMI and User Experience and/or a different application standard than what GENIVI ships with GDP Master. Changes to the underlying platform shall be fed back into GDP Master (and consequently shared with other spins).
One such example is the GENIVI Qt Automotive Suite Spin.
*Note that all companies are encouraged to base their development on the GDP open source code, for innovation, component development, for showcase demos, and so on. A GDP Spin is only a variation done in closer collaboration with GENIVI, and advertised as a more "official" variation. A Spin must serve a particular purpose as described above.