In PyCharm, there is a vertical line as highlighted on the screenshot. When I copy a long line of code into the editor, it wraps automatically if longer than this line. <img src="https://i.stack.imgur.com/Np5PU.jpg" alt="screenshot"> What is this line and what's its purpose?

It is a guide for the "hard wrap" setting. Setting screenshots from IntelliJ IDEA (PyCharm should be similar): <img src="https://i.stack.imgur.com/ZCOMN.png" alt="enter image description here"> <img src="https://i.stack.imgur.com/Ducnw.png" alt="enter image description here">