GL_ARB_texture_filter_anisotropic (based on GL_EXT_texture_filter_anisotropic) brings previously IP encumbered functionality into OpenGL to improve the visual quality of textured scenes.

GL_ARB_pipeline_statistics_query and GL_ARB_transform_feedback_overflow_query standardize OpenGL support for features available in Direct3D.

GL_ARB_indirect_parameters and GL_ARB_shader_draw_parameters for reducing the CPU overhead associated with rendering batches of geometry.

GL_ARB_gl_spirv and GL_ARB_spirv_extensions to standardize SPIR-V support for OpenGL.

OpenGL 4.6 adds the functionality of these ARB extensions to OpenGL’s core specification: OpenGL 4.6 adds support for ingesting SPIR-V shaders to the core specification, guaranteeing that SPIR-V shaders will be widely supported by OpenGL implementations. SPIR-V is a Khronos-defined standard intermediate language for parallel compute and graphics, which enables content creators to simplify their shader authoring and management pipelines while providing significant source shading language flexibility. OpenGL 4.6 integrates the functionality of numerous ARB and EXT extensions created by Khronos members AMD, Intel, and NVIDIA into core, including the capability to ingest SPIR-V™ shaders. J– SIGGRAPH 2017, Los Angeles, CA – The Khronos ™ Group, an open consortium of leading hardware and software companies, announces from the SIGGRAPH 2017 Conference the immediate public availability of the OpenGL® 4.6 specification.

OpenGL celebrates 25th anniversary with 4.6 release adding 11 ARB and EXT extensions into the core specification

Opengl 4.6 api specification