Clarification on MPT Proof Structure and Node Encoding

Hi,

I am working with the trie-db crate and have been generating Merkle-Patricia Trie (MPT) proofs using the generate_proof function. I encountered a proof output that looks like this:

proof = [
    [128, 109, 246, 128, 40, 4, 143, 29, 173, 116, 217, 15, 202, 4, 160, 160, 243, 45, 95, 110, 28, 10, 153, 210, 113, 15, 3, 179, 233, 147, 5, 230, 153, 209, 209, 115, 128, 113, 191, 84, 118, 196, 215, 54, 25, 245, 52, 166, 200, 120, 122, 192, 104, 97, 253, 158, 24, 160, 177, 164, 114, 199, 9, 134, 60, 181, 222, 73, 243, 128, 136, 241, 139, 11, 150, 112, 108, 214, 87, 218, 133, 54, 61, 148, 207, 31, 88, 253, 222, 179, 177, 188, 198, 2, 133, 37, 168, 62, 129, 114, 253, 70, 128, 7, 163, 189, 250, 136, 142, 195, 195, 218, 59, 238, 243, 80, 253, 40, 152, 129, 165, 178, 131, 84, 196, 240, 8, 153, 237, 215, 189, 219, 47, 245, 58, 128, 11, 205, 1, 140, 183, 171, 19, 47, 147, 84, 153, 120, 73, 28, 170, 198, 246, 78, 95, 231, 36, 245, 98, 230, 117, 179, 163, 83, 179, 251, 184, 64, 0, 128, 48, 211, 8, 232, 219, 71, 172, 102, 249, 135, 136, 147, 93, 36, 70, 176, 85, 77, 95, 80, 246, 11, 121, 225, 79, 70, 115, 223, 48, 221, 117, 129, 128, 11, 242, 134, 219, 251, 72, 136, 31, 143, 118, 204, 30, 82, 119, 15, 192, 71, 77, 87, 3, 107, 161, 162, 237, 75, 19, 210, 7, 42, 15, 242, 195, 128, 9, 254, 94, 221, 144, 61, 92, 14, 157, 39, 103, 206, 173, 229, 219, 72, 95, 128, 151, 203, 214, 134, 216, 182, 96, 86, 108, 200, 86, 214, 110, 19, 128, 36, 255, 147, 74, 29, 85, 43, 167, 7, 132, 117, 60, 77, 200, 129, 26, 110, 25, 31, 16, 153, 7, 223, 150, 157, 184, 196, 37, 103, 57, 62, 105, 128, 175, 47, 204, 105, 72, 112, 255, 4, 235, 59, 5, 241, 155, 67, 73, 40, 194, 149, 151, 243, 142, 118, 139, 128, 140, 86, 180, 199, 167, 216, 121, 56],
    [128, 9, 0, 0, 128, 36, 25, 119, 113, 142, 246, 194, 73, 178, 154, 190, 114, 81, 232, 29, 114, 221, 10, 219, 104, 242, 170, 181, 114, 11, 19, 82, 255, 88, 163, 179, 197],
    [129, 5, 8, 32, 128, 152, 165, 197, 189, 19, 246, 122, 169, 52, 148, 27, 239, 143, 45, 182, 20, 157, 237, 67, 252, 163, 157, 162, 215, 192, 118, 168, 126, 248, 132, 182, 89, 0],
    [124, 101, 29, 221, 150, 105, 99, 28, 218, 101, 196, 107, 225, 80, 95, 11, 189, 109, 181, 202, 69, 33, 248, 233, 106, 239, 33, 148, 86, 180, 20, 0]
]

I understand that each Vec<u8> probably represents an encoded trie node, but I'm having trouble interpreting the structure and meaning of each node in the proof. I'm trying to understand:

• The type of each node (e.g., branch, extension, leaf).
• How these nodes collectively represent a proof of inclusion or exclusion for a particular key.

Could you please provide guidance or documentation on how to decode and interpret these proof nodes/values?

Thank you for your help!

(Mention to be pinged: @algomaster99, @javierron)

Start with the trie-db crate's generate_proof function and follow the node-encoding implementation to identify how each Vec is serialized. Compare the generated proof with its target key to document node types and how the sequence establishes inclusion or exclusion. Done when the encoding and proof traversal are explained with a concrete decoding example.