What is the frequency of the PWM pins of an Arduino Uno?

/*
 * This sketch constantly sends PWM signals to all
 * Arduino UNO PWM pins so they can be observed 
 * via an oscilloscope.
 * 
 * Written by Ahmad Shamshiri
 * on Saturday, June 15, 2019 at 16:14
 * in Ajax, Ontario, Canada
 * www.Robojax.com
 * Watch the video instruction:  https://youtu.be/6O9SFvEP6Bs
 */
int pwmPin[] ={3, 5, 6, 9, 10, 11};// all PWM pins
#define controlPin A0

void setup() {
  // Robojax.com
  
  for(int i=0; i<6; i++){
    pinMode(pwmPin[i],OUTPUT);    
  }

 
  Serial.begin(9600);

}

void loop() {
  //Robojax.com
  int potValue = analogRead(controlPin);
  int pwm =map(potValue, 0,1023, 0, 255);
  Serial.print(potValue);//print pot value 0-1023
  for(int i=0; i<6; i++){
    analogWrite(pwmPin[i],pwm);
  } 
  Serial.print(" ");// prints an empty space
  Serial.println(pwm);// prints PWM value 0-255
  //delay(5000);
}