Wrote a parser to extract image metadata once, and got massively frustrated with the amount of undocumented, semi-documented, wrongly documented, or partially documented attributes. You’ll find references online, but most of them lack half of what you encounter in images. Every image processing app under the sun adds its own range. Some use metric values, some imperial; finding out which can be guesswork. Aperture is given in f-stops, decimals, or literal fraction strings. Some attributes hold sentinel values. Some vendors have custom conventions for undefined data.

It’s a jungle out there.

FYI: I just recently added simple Exif viewing/editing/clearing to my "xv"-inspired image editor pxv: https://github.com/linsomniac/pxv

My primary goal was to have my core "xv" muscle-memory usable through a simple tool that didn't require me building the original xv (since you can't just apt install it), because these days I'm not using xv much.

But I've since added a few features that xv doesn't have like the Exif and also image annotation, plus beefed up the image enhancement to be very much like XVs.

Exif is technical debt in the most flattering sense. Messy, old, and still quietly useful decades later.

Exif is great but here is your obligatory reminder that if you are publishing images you should strip out some of the identifying information that cameras and image editing software likes to embed.

In particular, you probably don’t want the GPS coordinates of your house publicly available on your blog for everyone to see.