[SavedModel Fingerprinting] Add documentation regarding project implementation.

tensorflow/community#415

PiperOrigin-RevId: 495996544

Author: Monica Song

tensorflow/python/saved_model/fingerprinting.md

@@ -0,0 +1,26 @@
+## SavedModel Fingerprinting
+
+This document describes the implementation details of SavedModel fingerprinting. 
+The design document (RFC) can be found [here](https://github.com/tensorflow/community/pull/415).
+
+### Implementation
+
+The code that implements SavedModel fingerprinting can be found in :
+- `tensorflow/python/saved_model/fingerprinting.py`: Public python methods for accessing the fingerprint.
+- `tensorflow/python/saved_model/pywrap_saved_model_fingerprinting.*`: Python wrappers for C++ fingerprint methods. For internal use only.
+- `tensorflow/cc/saved_model/fingerprint.*`: C++ methods for creating and reading the fingerprint.
+- `tensorflow/core/graph/regularization/`: Code that "regularizes" the GraphDef. See the README
+
+Generally speaking, most of the implementation for SavedModel fingerprinting is in C++. The code in this directory is meant to make these methods accessible in Python for the purposes of creating a public API
+as well as instrumenting the Python side of the code base.
+
+### Instrumentation
+
+The current SavedModel reading and loading APIs are instrumented such that they log
+the fingerprint every time they are called. The APIs that are instrumented are:
+- `tf.saved_model.save`
+- `tf.saved_model.load`
+- `tensorflow::LoadSavedModel`
+- `tensorflow::SavedModelV2Bundle::Load`
+
+