What does the TIFF tab show in macOS Preview’s Inspector metadata view?

I downloaded Carl Siebert's Metadata Test Image, which has unique values in many metadata fields, and I then edited it to have unique values in the timestamps for when taken and when digitized. For the fields I checked (primarily description/caption, copyright, date taken, and date digitized), the MacOS Preview Inspector showed the values stored in the IPTC metadata. This was regardless of the tab in the Inspector, so even the Exif tab appears to pull from the IPTC metadata.

The answer to the question thus appears to be that the TIFF tab shows IPTC metadata, but so does the Exif tab (and, as one would hope, the IPTC tab).

-----Update-----

I did some additional tests. If Exif, IPTC, and XMP metadata are all present, all tabs show IPTC metadata. If there is no IPTC metadata, but Exif metadata is present, all tabs (including the IPTC and TIFF tabs) show Exif metadata. If both IPTC and Exif metadata are missing, all tabs show XMP metadata (assuming it's there). It thus appears that the tab labels are entirely cosmetic. Data for all tabs are drawn from a single metadata source.

I would be grateful if someone would try to reproduce these results, because they're counterintuitive, and I worry that I did something wrong.