SafeTx-Protocol

    let ix = SafetxIx::try_from_slice(data).map_err(|_| ProgramError::InvalidInstructionData)?;     match ix {        SafetxIx::InitRegistry => init_registry(program_id, accounts),        SafetxIx::PushMetric(s) => push_metric(program_id, accounts, s),    }} fn init_registry(program_id: &Pubkey, accounts: &[AccountInfo]) -> ProgramResult {    let acc_iter = &mut accounts.iter();    let admin = next_account_info(acc_iter)?; // signer who becomes admin    let registry = next_account_info(acc_iter)?; // PDA to be created    let system_program = next_account_info(acc_iter)?;     if !admin.is_signer {        return Err(ProgramError::MissingRequiredSignature);    }     // Derive PDA: seeds = [b"safetx", admin]    let (pda, bump) = Pubkey::find_program_address(&[b"safetx", admin.key.as_ref()], program_id);    if pda != *registry.key {        msg!("Registry PDA mismatch");        return Err(ProgramError::InvalidSeeds);    }

1. Line 79 // Derive PDA: seeds = [b"safetx", admin]: Declares the PDA seeds. Anchor re-derives the address and rejects the account if it doesn't match.
2. Line 80 let (pda, bump) = Pubkey::find_program_address(&[b"safetx", admin.key.as_ref()], program_i: Derives a PDA from seeds and the program ID and returns the address with its canonical bump.
3. Line 80 let (pda, bump) = Pubkey::find_program_address(&[b"safetx", admin.key.as_ref()], program_i: Uses the bump seed, the extra byte that pushes the derived address off the ed25519 curve.
4. Line 82 msg!("Registry PDA mismatch");: Logs to the program log, which is visible in explorers and the test output.