It's not clear to me if dropping support for this functionality was intentional.

Chain of events:

- #21689 removed test coverage due to a misunderstanding due, I believe, to this functionality being generally supported by all platforms except macOS which does not and returns a different format
- #21756 removed support and caused this regression
- #21690 restores the test coverage that would have caught this regression

Currently, neither the test coverage before #21689 nor the coverage restored by #21690 pass since the merge of #21756.

strprintf("BIP155 TORv3 address with length %u (should be %u)", address_size,
                      ADDR_TORV3_SIZE));
    case BIP155Network::I2P:
        if (address_size == ADDR_I2P_SIZE) {
            m_net = NET_I2P;
            return true;
        }
        throw std::ios_base::failure(
            strprintf("BIP155 I2P address with length %u (should be %u)", address_size,
                      ADDR_I2P_SIZE));
    case BIP155Network::CJDNS:
        if (address_size == ADDR_CJDNS_SIZE) {
            m_net = NET_CJDNS;
            return true;
        }
        throw std::ios_base::failure(
            strprintf("BIP155 CJDNS address with length %u (should be %u)", address_size,
                      ADDR_CJDNS_SIZE));
    }
    
    
    
    return false;
}
/**
 * Construct an unspecified IPv6 network address (::/128).
 *
 * @note This address is considered invalid by CNetAddr::IsValid()
 */
CNetAddr::CNetAddr() {}