Help with frame Payload understanding

Hello, I’ve been working with a Sigfox dev kit that uses Arduino as main board, there isn’t enough information or sample codes of this kit but found this online, it take temperature readings from sensor when acceleration on X axis is detected:

// Include librairies
#include <WISOL.h>
#include <Tsensors.h>
#include <Wire.h>
#include <math.h>
Isigfox *Isigfox = new WISOL();
Tsensors *tSensors = new Tsensors();
// Init function
void setup() {
  Wire.begin();
  Wire.setClock(100000);
  // Init serial connection between Arduino and Modem
  Serial.begin(9600);
  // WISOL modem test
  Isigfox->initSigfox();
  Isigfox->testComms();
  // Init sensors on Thinxtra Module
  tSensors->initSensors();
  // Init an interruption on the button of the Xkit
  tSensors->setButton(buttonIR);
}
// Infinite loop of the program
void loop() {
  float axeX = getAxeX();
  Serial.print("Check Axe X: "); Serial.println(axeX);
  if (axeX <= -0.4 or axeX >= 0.4) {
    // Get Temperature
    float temp = getTemp();
    // Send Temperature to Sigfox
    Send_Pload((const char*)&temp, sizeof(temp));
    // Wait 20s
    delay(20000);
  }
  delay(1000);
}
// Return the acceleration on Axe X
float getAxeX() {
  acceleration_xyz *xyz_g;
  xyz_g = (acceleration_xyz *)malloc(sizeof(acceleration_xyz));
  tSensors->getAccXYZ(xyz_g);
  float axeX = (float)xyz_g->x_g;
  free(xyz_g);
  return axeX;
}
// Get the temperature
float getTemp() {
  float temp = round(tSensors->getTemp() * 10) / 10.0;
  Serial.print("Sending Temp: "); Serial.println(temp);
  return temp;
}
// SendPayload Function => Send messages to the Sigfox Network
void Send_Pload(uint8_t *sendData, int len) {
  recvMsg *RecvMsg;
  RecvMsg = (recvMsg *)malloc(sizeof(recvMsg));
  Isigfox->sendPayload(sendData, len, 0, RecvMsg);
  for (int i = 0; i < RecvMsg->len; i++) {
    Serial.print(RecvMsg->inData[i]);
  }
  Serial.println("");
  free(RecvMsg);
}
// Button Interruption
void buttonIR(){
    float temp = getTemp();
    Send_Pload((const char*)&temp, sizeof(temp));
}

My question is how Send_Pload function works, please I need help to understand it.