Original BLINK doesn't work on Web editor

I'm getting back into the Arduino after a few years away. I noticed the classic Blink example has been changed.

Instead of using
pinMode(13, OUTPUT);

it's now
pinMode(LED_BUILTIN, OUTPUT);

The original classic pinMode(13, OUTPUT); still works fine on the desktop IDE 1.8.16, but on the web editor I get a compile error and was wondering why.

Errors below...
/tmp/261473610/BLINK_old_style/Blink.ino: In function 'void setup()':

/tmp/261473610/BLINK_old_style/Blink.ino:9:6: error: redefinition of 'void setup()'

void setup() {

^~~~~

/tmp/261473610/BLINK_old_style/BLINK_old_style.ino:3:6: note: 'void setup()' previously defined here

void setup()

^~~~~

/tmp/261473610/BLINK_old_style/Blink.ino: In function 'void loop()':

/tmp/261473610/BLINK_old_style/Blink.ino:15:6: error: redefinition of 'void loop()'

void loop() {

^~~~

/tmp/261473610/BLINK_old_style/BLINK_old_style.ino:8:6: note: 'void loop()' previously defined here

void loop()

^~~~

Error during build: exit status 1

Weird. I think the file was corrupt. I modified the new built in BLINK to use the old variables and now it compiles correctly.

Looks like you accidentally got both .ino files in the same project.