From his footnotes:

> I was able to find a reasonable amount of AVIF HDR images, but HEIC HDR is nowhere to be found.

Anything taken by an iPhone camera is an HDR HEIF image… sort of. For backwards compatibility reasons it's an SDR image with an additional attached image called a gain map that HDRifies it. (This is mathematically worse for a reason I don't remember; it causes any picture taken at a concert with blacklights or blue spotlights to look bad. Once you see this you'll never unsee it.)

I believe the very newest Sony cameras can also save HEIF images, however I don't feel like spending $2500 to upgrade my second-to-newest A7 to a newest A7 to find out.

Lightroom also recently added HDR editing so maybe it can export them now?