My self compiled ART builds are only populating lensfun with my custom lens profiles. RT picks up both custom and official profiles from my local folder. I can’t see to figure out what sets the installations apart.
The lensfun set up is in
.local/share/lensfun/
With my custom xml files of lenses I’ve profiled myself at
.local/share/lensfun/lensfun.xml
and the profiles updated with the lensfun-update-data command in
.local/share/lensfun/updates/version_1/
Again with ART I only see my self made profiles. The setup as per above is ancient and has been working for maaany years.