Describe the enhancement requested
After #44714, the C++ implementation no longer drops field metadata (e.g., extension type information) from key or value items in the map type. We should add a test case to make sure other implementations can do this too! I think the scope of this is just an Archery test case (but could maybe also be an IPC file in arrow-testing?).
(As suggested in #44715 (comment) ).
Component(s)
Integration