`banlist.dat` was introduced in https://github.com/bitcoin/bitcoin/pull/6310, storing nodes that were automatically banned (due to exceeding the misbehavior threshold) and manually banned (through the `setban` RPC).

Automatic bans were removed in https://github.com/bitcoin/bitcoin/pull/19219 and replaced with a discouragement filter. That filter is not saved to disk/persisted over shutdown/startup. The `banlist.dat` therefore now only contains addresses that have been banned through the `setban` rpc.

Since https://github.com/bitcoin/bitcoin/pull/15935, we have a specific file for configuration that is updated through the RPC and persisted over shutdown/startup, namely `settings.json`. We should therefore move the manual ban configuration from `banlist.dat` to `settings.json`. Doing so has a couple of benefits:

- `settings.json` is human readable and easily analyzable by any json parser.
- we wouldn't need to maintain custom [de]serialization code for the `banlist.dat` file.

`banlist.dat` is expected to be fairly small and infrequently updated, so disk space/performance are not huge concerns.
for (const CNode *node : vNodes) {
        BOOST_CHECK(node->fDisconnect == false);
    }
    
    
    
    AddRandomOutboundPeer(vNodes, *peerLogic, *connman);
    peerLogic->CheckForStaleTipAndEvictPeers();
    for (int i = 0; i < max_outbound_full_relay; ++i) {
        BOOST_CHECK(vNodes[i]->fDisconnect == false);
    }
    
    BOOST_CHECK(vNodes.back()->fDisconnect == true);
    vNodes.back()->fDisconnect = false;
    
    
    UpdateLastBlockAnnounceTime(vNodes.back()->GetId(), GetTime());
    peerLogic->CheckForStaleTipAndEvictPeers();
    for (int i = 0; i < max_outbound_full_relay - 1; ++i) {
        BOOST_CHECK(vNodes[i]->fDisconnect == false);
    }
    BOOST_CHECK(vNodes[max_outbound_full_relay-1]->fDisconnect == true);
    BOOST_CHECK(vNodes.back()->fDisconnect == false);
    for (const CNode *node : vNodes) {
        peerLogic->FinalizeNode(*node);
    }
    connman->ClearTestNodes();
}
BOOST_AUTO_TEST_CASE(peer_discouragement)