With regards to Xonotic, the XPM/Xonotic Promode they want is more to do with item balance (tiered armors, timing) The default Xonotic movement is close to CPM physics, but there are some differences. Osiris was suggesting it be tweaked in XPM to better match CPM. Some of the CPM code was released, and that has found its way into many projects. Xonotic also has some QuakeWorld and Warsow movement code (or perhaps a reimplementation) And I trust Astral to stay true to well-known strafing and trick-jumping - I play DeFRaG with him almost daily.