Per this commit yesterday, here's a list of OpenGL extensions that are newly supported by core Mesa with the forthcoming 9.1 release:
GL_ANGLE_texture_compression_dxt3: An OpenGL extension from Google for doing the same as the EXT_texture_compression_dxt1 extension but also exposing the COMPRESSED_RGBA_S3TC_DXT3_ANGLE compression format.
GL_ANGLE_texture_compression_dxt5: An OpenGL extension from Google for doing the same as the EXT_texture_compression_dxt1 extension but also exposing the COMPRESSED_RGBA_S3TC_DXT5_ANGLE compression format.
GL_ARB_ES3_compatibility: The GL_ARB_ES3_compatibility extension is for exposing features of OpenGL ES 3.0 that are otherwise missing from the OpenGL 3.x specification. This extension makes it easier for porting applications from OpenGL ES 3.0 to OpenGL for the desktop. Among the functionality that's then exposed for GL3 includes conservative boolean occlusion queries, primitive restart with a fixed index, and the OpenGL ES Shading Language 3.00 specification.
GL_ARB_internalformat_query: The GL_ARB_internalformat_query extension comes largely from ARM and TransGaming and NVIDIA with the purpose of adding a query mechanism that allows the software to determine sample counts for specific internal formats.
GL_ARB_shading_language_packing: This OpenGL extension allows for converting a 32-bit unsigned integer holding a pair of 16-bit floating-point values to/from a two-component floating-point vector.
GL_ARB_texture_cube_map_array: This extension builds upon the GL_EXT_texture_array extension to expand texture array support for handling cube-map textures.
GL_EXT_color_buffer_float: This OpenGL extension is for allowing floating-point formats to be rendered via frame-buffer objects (FBOs). Sadly, this is one of the OpenGL extensions in a patent/IP mess due to its floating-point use.
GL_OES_depth_texture_cube_map: The extension provides a new texture generation scheme for cube-map textures.
These new OpenGL extensions to Mesa 9.1 just cover a small portion of the improvements made to Mesa over the past six months from hardware driver improvements, performance enhancements, new Gallium3D state tracker features, and much more. Expect more Phoronix articles to recap the Mesa 9.1 changes leading up to the official release by the end of February.