NSWidgetBackgroundColorName
The name of a color in an asset catalog to use for a widget’s configuration interface.
Discussion
This Info.plist value controls the background color shown in the widget configuration interface while editing a widget.
While you can set this directly in your Info.plist, the recommended approach is to use the Widget Background Color Name build setting (in the Asset Catalog Compiler - Options section) of the widget extension target. Set the value of the build setting to the name of the Color Set in the asset catalog. Xcode automatically sets NSWidgetBackgroundColorName to the appropriate value in the Info.plist file when building your project.