Being a bit of hipster (I’m doing photography using Linux and open source software for heaven’s sake) and am switching my workflow to use HEIF files as a sort of “raw-lite” format. Darktable processes the images just fine, but it is not exporting the EXIF data with the JPEGs. The security-conscious members of the community would say this is a good thing, but I have enabled all of the bits needed to export EXIF data (for posting to flickr) but that section of the image is bereft of any data. Processing a RAF file (I shoot Fuji) operates as expected. So, “why do I want to use HEIF files” you ask? For the film simulations. Fuji is still a film company and their engineers produce some of the best film simulations I have ever seen in my 48 years as a photographer. Nothing short of shooting with the actual film comes close. The RAW files may show a preview with the film simulation, but the moment you open the RAW file, it reverts to the base profile. Nothing I do comes even close to the image captured in HEIF format. HEIF, being lossless and 10-bit, has quite a bit more flexibility than JPEGs and can export lovely 1st gen JPEGs all day long.
For the record, the EXIF data is displayed for the HEIF file in darktable. It’s just not exported to JPEG.
Here is a link to a sample image for all to play with: