I'm using latest bitcoincore release thus,, upon my investigation inside the wallet.dat file I can find a ckeyA which corresponds to the passcode been used to lock this wallet 'cause on my new default_wallet I cannot see any ckeyA that corresponds to my passcode which was 0919 but on the other hand of wallet.dat file I see ckeyA but after that a gibberish presentation I'f I could only knew what Berkeley using to hash this encrypted password I could perhaps somehow decrypt it using reverse engineering,
ckey is not the hashed password nor is it the password encrypted. A
ckey record is followed by the public key, which is then followed by the encrypted private key. You are looking at the completely wrong place. The
A is because the pubkey is prepended by its length which is 0x41 which happens to be the ascii A.
If you want to "reverse engineer" your passphrase, then use
https://github.com/gurnec/btcrecover to do it for you. You aren't going to learn it yourself by inspecting the wallet.dat file, it's not in there in plaintext. And you clearly don't understand the wallet format because you are chasing the completely wrong thing. This tool has already been written to do all that for you.