Modem status, SNR and RSSI. Semtech SX1278 datasheet:

void loop() {
  uint8_t r = sx1278.receiveAll();

#if (debug_mode > 0)
  Serial.print(F("receiveAll: "));
  Serial.println(r, DEC);

  if (r == 0) {
    Serial.println(F("Packet data: "));
    for (r = 0; r < sx1278.packet_received.length; r++) {
      Serial.print([r], HEX);
      rxPacket[r] = (char)[r];
      if (r == rxPacketLen - 1) {
    uint8_t modemStat = sx1278.readRegister(REG_MODEM_STAT);
    Serial.print(F("RegModemStat: B"));
    Serial.print(modemStat, BIN);
    int8_t snr = sx1278.getSNR();
    Serial.print(F("Estimation of SNR on last packet received (dB): "));
    Serial.print(snr, DEC);
    int16_t rssiPacket = sx1278.getRSSIpacket();
    Serial.print(F("RSSI of the latest packet received (dBm): "));
    Serial.print(rssiPacket, DEC);         
    memset(rxPacket, 0, sizeof(rxPacket));

Other interesting features:
RegDetectOptimize (0x31)
Bits 2-0
LoRa Detection Optimize
0x03 -> SF7 to SF12 (default value), 0x05 -> SF6

RegInvertIQ (0x33)
Bit 6
Invert the LoRa I and Q signals
0 -> normal mode (default value), 1 -> I and Q signals are inverted

RegSyncWord (0x39)
LoRa Sync Word, default value 0x12
Value 0x34 is reserved for LoRaWAN networks

RegDetectionThreshold (0x37)
LoRa detection threshold
0x0A -> SF7 to SF12 (default value), 0x0C -> SF6

SX1278 LoRa CAD mode (channel activity detection) does not work properly, probably it is too sensitive.