I have no clue.

Whats even more irritating is, that listing the COM interfaces via

def getIidsOfComObject(com):
    import ctypes
    from win32more import POINTER, Guid, UInt32

    count = UInt32()
    guids = POINTER(Guid)()

    hr = com.GetIids(ctypes.byref(count), ctypes.byref(guids))
    if hr != 0:
        raise ctypes.WinError(hr)

    return [ str(guids[i])[1:-1] for i in range(0, count.value) ]

with

listView = xamlElement.as_(ListView)

on the ListView itself

getIidsOfComObject(listView)

works, but on the ItemsSource as

getIidsOfComObject(listView.ItemsSource)

fails with a ValueError: NULL COM pointer access ...

The function is called from the main thread, printing via

print(listView, listView.ItemsSource)

works and shows <ListView object at 0x..> <IInspectable object at 0x...> as expected. But without getting the Interfaces of the ItemsSource object I have no clue what and how to create one myself...

The ListView was created via XAML like:

<ListView>
  <x:String>Hello Python!</x:String>
  <x:String>Hello win32more!</x:String>
</ListView>

and the strings show up, so I guess there is an ItemsSource.