Ok, I found it inside the Resolve 19 new features guide:
https://documents.blackmagicdesign.com/ ... _Guide.pdfSupport for HDR Displays on Windows*
You can now display the native viewers in DaVinci Resolve in HDR on Windows systems.
The setting affects all DaVinci Resolve Viewers, including the Main Page Viewers, Cinema Mode,
Fairlight Floating Viewer, Scene Cut Dialog, and the Video Clean Feed.
You will need an HDR-capable display and to turn on HDR in the Windows display settings
(System > Display > HDR). In DaVinci Resolve Preferences > System > General, you will need to
check the “Use 10-bit precision in viewers if available” box.
NOTE: The general controls/UI and non-Viewer dialogs (e.g., secondary screen, project
manager, floating Media Pool) are not affected.
* As of this writing, HDR Displays on Windows was not available but will be included in the final release.