Is there a default var that contains current filename of sketch ?

Projects Programming
2

__FILE__ is worth looking into.

void setup() {
   while( !Serial && millis() < 5000 );
   Serial.begin(115200);
   Serial.println(__FILE__);
}

void loop() {
}

Monitor port settings:
baudrate=115200
Connected to /dev/ttyUSB1! Press CTRL-C to exit.
/home/me/Documents/sketchbook/Uno_R3/test/test.ino