A. I recall the discussion on adding a gallery mode to discuss. The thing is that the mountains have lots of fine detail so they would look much better when viewed on a larger (and higher quality) screen or mode. I suppose that I could make it suitable for 690px or smaller widths but that would not do justice for such a magnificent view.
B. I believe that this mode is present in many raw processors. My understanding is that it is a compromise between clip and unclip modes. In
dcraw, clip means that the multipliers go above
1 and values that exceed 255 or 65535 are clipped. Unclip means that the multipliers are normalized such that the greatest would be set to
1. That way, theoretically, there wouldn’t be any clipping from demosaicing.
The consequence of unclip is the possibility of color shift in the whites. Blend mode prevents that from happening. But I have noticed that the algorithm isn’t perfect and can actually produce clipping that is worse in appearance than clip itself.
dcraw has other blend modes as well (RT has even more but many of the principles are the same) but I typically stick with clip, unclip and blend because of their simplicity. The rest I would rely on G’MIC or GIMP, or in your case RT, to do the heavy lifting.