bfHDRView [1] is a macro for eyeon Fusion [2] which helps to visualize high dynamic range imagery. It shows floating point values that exists above 1.0 or below 0.0 in map mode or High/Low Mode.

MAP MODE is generally what Shake does in floating point view:
it shows the values below 0 black, the values between 0 and 1 grey and, values above 1 white

The HIGH/LOW MODE normalizes values above 1.0 (in High mode) or below 0 (in Low mode) to 0-1 so you can see what is going on and how much detail is hidden without having to find a correct LUT value.

[1] output (bfloch.com)
[2] eyeon fusion

..................................................