These are the headers for NVIDIA's OptiX ray tracing API. Usage of this
API allows for an application to offload its ray tracing calculations
to the system's onboard NVIDIA GPU card, potentially drastically
render speeds.
Currently, this is only present in the SlackBuilds.org repository as an
optional dependency for graphics/Blender. If this is installed, the
graphics/Blender SlackBuild will automatically detect the OptiX headers
and Blender will be built with support for OptiX, allowing to use it
for rendering, as well as GPGPU-accelerated image denoising.
This SlackBuild also requires a recent CUDA toolkit (probably newer
than the current one available in the SBo repository). It will install
without it, it just will be useless without it.