STEP #1:
Examples that use the acceleration sensor use the acceleration() method:

void loop() 
{
    acceleration();
    ...
}

STEP #2:
Within the acceleration method in the functions.h tab, you will find:
bool res = sensor->getAccel(acc);
...which refers to the object sensor.

STEP #3:
The sensor object is created in the twatch.h tab.
You can see that it is of type BMA:

BMA *sensor;
...
sensor = watch->bma;

STEP #4:
Im Verzeichnis..
/home/fhbstud/Arduino/libraries/TTGO_TWatch_Library-1.4.3/src/drive/bma423/
...in the header file for class BMA bma.h, there is a reference to the method 
...there is the method float temperature();

...This is now being tested:

Code 0-1: Examination of the functions and libraries provided.

#include "twatch.h"
#include "variables.h"
#include "functions.h"

void setup() 
{
    setupTWATCH();
    setFont(1, 255,255,255,  255,0,0);
    backlight(true); 
}

void loop() 
{
    clear();
    acceleration();

    cursor(0,0);

    editor(accX); 
    editor('\n');

    editor(accY); 
    editor('\n');

    editor(accZ); 
    editor('\n');

    float temp = sensor->temperature();
    editor(temp);
    editor('\n');
    
    delay(100);
}

Code 0-2: Sample program for reading the temperature.