Texture Buffer Objects were added to the core specification with OpenGL 3.0 and is a 1D texture backed by a buffer object. Uniform Buffer Objects are buffer objects storing uniform data and have been part of the specification since OpenGL 3.1. This R600 work by Red Hat's David Airlie came after he first did UBO/TBO for Gallium3D's Softpipe driver.
With the Texture Buffer Objects and Uniform Buffer Objects support, the R600g driver is now able to finally reach the state of supporting GL Shading Language 1.40. This version of GLSL is what's mandated by OpenGL 3.1. The only other Mesa hardware driver advertising GLSL 1.40+ at present is the Intel "i965" DRI driver.
The R600g UBO commit happened here while the R600g TBO and GLSL 1.40 enabler was here. The OpenGL 3.x status file was updated to reflect these driver improvements.
These improvements to this open-source GPU driver that supports from the ATI Radeon HD 2000 series through the AMD Radeon HD 6000 series will be found with next month's release of Mesa 9.1.