The following settings are available for the Post-FX:
While Depence renders in HDR (High Dynamic Range) values, the Tone-Mapper defines how HDR image gets composed back into an LDR image.
The auto-exposure will detect the average intensity on screen, and levels the current Camera Exposure automatically.
Furthermore, it offers different tone mapping techniques. The default and most realistic is called "Natural". When this tone mapper is active, the engine will calculate all colors in an ACEScg color space to provide a larger spectrum and simulate the behavior of real Cameras.
Using the Spectrum value it is possible to clamp the space to get back to plain sRGB values.