.qface file of QtInterfaceFramework is not highlighting

if QtInterfaceFramework example tutorials are opened in Qt Creator, .qface files are not highlighting, though documentation of image shows this does indent and colors are highlighted.

https://doc.qt.io/QtInterfaceFramework/qtinterfaceframework-interfaceframework-qface-tutorial-example.html#define-default-values

Qt Creator does shows a popup saying highlighting definition is not found and asks to download, but download button does nothing.