This will show all attributes and their values of an existing widget: (I got the idea from user285594 at this post)
obj = [widget identifier]
for pspec in obj.props:
print(pspec.name)
name = pspec.name.replace('-', '_')
props = eval("button.props." + name)
print(props)
Unfortunately, I can't find the attachment values when the widget has been attached to a grid. Does anyone know how to do this?