"visible
Show or hide this metadata field. Hidden fields are not displayed anywhere in darktable and are not be included in exported images.
private
Keep this metadata field private. Private fields are displayed within darktable but are not be included in exported images.
Fields with both options unchecked are displayed within darktable and included in exported images."
The ‘show/hide…not displayed anywhere in darktable’ property appears, on my system, (both Linux and Win. 10) to apply only to the metadata editor area (right-hand panel); info in the ‘file information’ area (left-hand panel) always shows metadata irrespective of whether ‘visible’ is checked or not.
Indeed it does (which I had not realised until you pointed it out) and which does allow we to toggle the visibility of many items (very useful). I think I was strongly influenced by the wording: 'not displayed anywhere in darktable’, which I read to include the file information area.
Shouldn’t that part of the manual say ‘… not displayed anywhere within the metadata editor’ ? or perhaps mention the effect that the preferences within the file information module actually control the display of metadata information in that module?