- To clear the previous settings, click
icon choose Clear Imported Settings.
Those options in the 'calibration tab' are similar to those you get in the 'basic' tab from the drop-down menu you access from the small icon on the right of the 'basic' bar.
- Image settings shows the edits applied previously to that image
- camera raw defaults shows the edits linked to the standard profile of your camera model, or the modified ones created in the 'calibration' tab.
- Previous conversion remembers the settings applied to the last edited image. It's extremely useful: you can apply the same edits as any previously edited file by opening that file sample, saving with 'Done' and then opening one or several images and choosing 'previous conversion'. That acts like a 'preset'.
For the explanation about the process, see the help from the help button.