Intel Blackhole Render support was finally merged today for the new Intel "Iris" Gallium3D OpenGL driver default, the older i965 driver for pre-Broadwell hardware, and also the Mesa state tracker for Gallium3D drivers.

Proposed back in 2018 was the Intel blackhole render extension for OpenGL / GLES as an extension to disable all rendering operations emitted to the GPU through OpenGL rendering commands but without affecting OpenGL pipeline operations.

That extension, INTEL_blackhole_render, saw patches back around that point while now finally for Mesa 20.1-devel this Intel OpenGL extension is seeing mainline support for all drivers.

The INTEL_blackhole_render extension is principally useful for debugging / driver optimization analysis purposes. One of the driving motivators appears to be for analyzing the Intel kernel driver execbuffer overhead.

So INTEL_blackhole_renderer is now the latest OpenGL extension in Git for next quarter's Mesa 20.1.