How to get the underlying TFHE bootstrapping and keyswitch keys information

[Checiii]

Help Needed: Accessing LWE Ciphertext and Bootstrap Key Components in Concrete-ML
Running use_case_examples/cifar/cifar_brevitas_training/evaluate_one_example_fhe.py.
Current access:

circuit.keys.evaluation for evaluation keys
circuit.keys.serialize() → 103,343,257 bytes
circuit.size_of_bootstrap_keys → 663,322,624 bytes

Need to:

Access LWE ciphertext's b component in KeySwitch keys
Access Bootstrap key components
Understand size discrepancy between serialized (103M) vs theoretical (663M) data

Code analysis shows standard interfaces (serialization, cpp objects) but no direct component access. Any guidance on accessing these key components would help.