EXIF tag ImageUniqueID not exported

Is there an existing issue for this?

• I checked and did not find my issue in the already reported ones

Describe the bug

EXIF tag ImageUniqueID not exported

Steps to reproduce

1. go to export preferences
2. uncheck EXIF Data
3. add an output metadata tag: Xmp.exif.ImageUniqueID
4. set formula to "="
5. save preferences
6. export any image to jpg, for example
7. check exiftool -s3 -ImageUniqueID image.jpg
8. observed result: "="
   expected: the actual ImageUniqueID from the raw file

Expected behavior

No response

Logfile | Screenshot | Screencast

No response

Commit

No response

Where did you obtain darktable from?

self compiled

darktable version

5.3.0-984

What OS are you using?

Linux

What is the version of your OS?

Linux Mint

Describe your system

No response

Are you using OpenCL GPU in darktable?

Yes

If yes, what is the GPU card and driver?

No response

Please provide additional context if applicable. You can attach files too, but might need to rename to .txt or .zip

No response

Reproduce the export using the listed preferences and verify the result with exiftool. Start by tracing darktable’s output-metadata handling for Xmp.exif.ImageUniqueID and compare it with the raw file’s EXIF value. Done means exporting a JPEG where ImageUniqueID contains the source value rather than "="; no source file or test is named in the issue.