what is the red arrow on the left of the line numbers in Sublime : <p><a href="https://i.stack.imgur.com/FiyG0.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FiyG0.png" alt="see the red arrow on the left of the picture"></a></p>

<p>what does the red arrow mean in Sublime text editor between line 13 and 14?</p>
