I was trying to sanity check the gain and offset of my camera (asi1600 native driver) while checking flat exposures in the control panel focus tab.
If you “save a mono fits” image from the context menu in the preview and then click on image headers, a dialog pops up and tells you there aren’t any headers because the image has not been saved.
Checking in a fits viewer, the image DOES have headers, however comparing the headers to a fits file saved from a sequence it is missing:
GAIN = 200 / Camera gain
EGAIN = 4.96000003814697 / Electrons Per ADU
OFFSET = 50 / Camera offset
Which was the data I was looking for.