(Not sure if this is an exif or libexif bug.)
exif --ifd=GPS --tag=0x01 somefile.jpg returns:
EXIF entry 'North or South Latitude' (0x1, 'GPSLatitudeRef') exists in IFD 'GPS':
Tag: 0x1 ('InteroperabilityIndex')
Format: 2 ('ASCII')
The first line is OK, as the code correctly honours the GPS IFD, but the rest of the dump has gotten mixed up with the Interoperability IFD, as it calls exif_entry_dump() which is really obsoleted since it ignores IFD. Like other libexif functions, it should probably be replaced by something like "exif_entry_dump_with_ifd()" .
NB The same probem will of course appear for tag 0x02 which also overlaps between IFDs.