Three of the new features do not have documentation in RawPedia, so I will try to explain them here. The other ones I hope are sufficiently documented. Let me know @patdavid if you think otherwise. I’m not an expert at all the new features, but will try my best to fill in any gaps.
Full-Screen/Detached Inspector
In the preferences, the full-screen inspector can be activated. When enabled, the inspector tab on the right panel of the file browser no longer appears. Instead, it is invoked by hovering the cursor over an image, then pressing and holding the f key. A new window will appear showing the entire embedded image in full-screen. Letting go of the f key will close the inspector window. Alternatively, pressing and holding Shift-f opens the inspector with the image at 100% zoom.
Clicking anywhere inside the inspector window while it is open will pin it. This allows further inspection of the image by panning (click-and-drag) and zooming (scrolling). Pressing f or Shift-f will fit the image to the window and zoom to 100%, respectively. The pinned inspector behaves like a normal window. This means it is possible to toggle the full-screen status, resize it, and move it around. The inspector can even be placed on a different screen for multi-monitor setups.
The detached inspector retains the image navigation of the tabbed inspector. By moving the cursor over the thumbnails in the file browser, one can inspect various regions of the image or switch between images.
Improved Film Negative
Film Negative made its appearance in RawTherapee 5.7. It inverts raw images of film negatives while accounting for the light response properties of film. Film Negative has been revamped to solve some of its shortcomings. The preview updates quicker when making adjustments, and a raw image is no longer required to enable the tool. Consequently, Film Negative now lives in the Color tab.
White balance has been split into two parts. The first stage involves setting the proper white balance of the backlight using the standard White Balance tool. Following the inversion process, the white balance of the scene recorded in the film can be adjusted within the Film Negative tool.
Dual-Demosaic with Bilinear
Several dual-demosaic options already exist in RawTherapee. They blend the results of two demosaicing algorithms together, using the one better suited for fine details on high-contrast areas of the image, and the one better suited for smooth regions on low-contrast areas.
Bilinear demosaicing is a fast method that produces good results for smooth regions. Three new dual-demosaic options combine bilinear demosaicing with AMaZE, RCD, and DCB.