private static SECPSignature parseProposerSeal(final Bytes proposerSealRaw) {
    return proposerSealRaw.isZero()
        ? null
        : SignatureAlgorithmFactory.getInstance().decodeSignature(proposerSealRaw);
  }
Gets proposer address.

@return the proposer address
consensus/clique/src/main/java/org/hyperledger/besu/consensus/clique/CliqueExtraData.java