Here is a list of all enum values with links to the classes they belong to:

Jamaica : QLocale
JamoScript : QLocale
January : QQuickCalendar
Japan : QLocale
JapanBlush : QGradient
Japanese : QFontDatabase, QLocale
JapaneseScript : QLocale
Javanese : QLocale
JavaneseScript : QLocale
JavaScript : QQmlMetaType
Javascript : QQmlProfilerDefinitions
JavaScriptBuiltin : QQmlJSScope
JavaScriptFile : QQmlAbstractUrlInterceptor, QQmlDataBlob
JavaScriptOwnership : QJSEngine
JavaScriptType : QQmlType
Jersey : QLocale
JisB0 : QPageSize
JisB1 : QPageSize
JisB10 : QPageSize
JisB2 : QPageSize
JisB3 : QPageSize
JisB4 : QPageSize
JisB5 : QPageSize
JisB6 : QPageSize
JisB7 : QPageSize
JisB8 : QPageSize
JisB9 : QPageSize
Jju : QLocale
Join : QQnxAbstractVirtualKeyboard
JointAndWeight : QSSGShaderKeyVertexAttribute
JointSemantic : QQuick3DGeometry::Attribute, QSSGMesh::RuntimeMeshData::Attribute
JolaFonyi : QLocale
Jordan : QLocale
JoystickPeripheral : QBluetoothDeviceInfo
JP2 : ICNSEntry
JPEG : AndroidCamera, QImageCapture
JsTyped : QV4::Function
JsUntyped : QV4::Function
JuicyCake : QGradient
JuicyPeach : QGradient
July : QQuickCalendar
JunctionName : QAbstractFileEngine
JunctionType : QFileSystemMetaData
June : QQuickCalendar
JungleDay : QGradient
JUnitXML : QTestLog
JustifyCenter : QQuickFlexboxLayout
JustifyEnd : QQuickFlexboxLayout
JustifyKashida : QGlyphJustification
JustifyNone : QGlyphJustification
JustifySpace : QGlyphJustification
JustifySpaceAround : QQuickFlexboxLayout
JustifySpaceBetween : QQuickFlexboxLayout
JustifySpaceEvenly : QQuickFlexboxLayout
JustifyStart : QQuickFlexboxLayout