The bridge_type() API should accept a new `default_property` keyword argument which adds the default property class info to the metaobject.

eg:     bridge_type(Box, uri="backend", version="1.0", default_property="child")

QML code:
Box {
id: testBox
// Widget will be assigned to child property
Widget

}
 
Python class:
class Box:
"""Container with a single child widget"""
def_init_(self):
self._child=None

@property
defchild(self) -> Widget:
returnself._child

@child.setter
defchild(self, value: Widget) -> None:
self._child=value

defhas_child(self) -> bool:
returnself._childisnotNone