I read through all specifications of https://entethalliance.github.io/client-spec/qbft_spec.html, and also https://besu.hyperledger.org/en/stable/
It talks about QBFT, but nowhere exactly mentioned what is Q?
BFT is for Byzantine Fault Tolerant, Assuming Q means Quorum here?
The Q is for Quorum - QBFT is implemented in both GoQuorum and Besu.