Customize the Exif tags shown under 'Image information'

Hi
I am new to darktable. I am using darktable 2.4.2 on Ubuntu 16.04.

By default darktable shows few Exif tags under ‘Image Information’ panel. I would like to extend it to show Exif.MakerNote tags also. Specifically, I am interested in following tags.
Exif.MakerNote.FocusMode
Exif.MakerNote.AFAdjustment

Is there a way to customize it? If this requires writing lua script, please let me know how to go about.

Thanks