How to obtain geometry mapping in python?

Here’s my geometry node setup that converts each quad face to 16 vertices. For example, face 19 is converted to vertex 81 233 234 77…13.

Is there a way to find the mapping between generated vertices(or faces) and original face id in python?

You can store the original index on the geometry nodes side (might need some sample index trickery) and then read the resulting attribute from the python side.