How can PHP developers ensure that the source code displayed on a webpage is properly formatted and easy to understand for users?

PHP developers can ensure that the source code displayed on a webpage is properly formatted and easy to understand for users by using syntax highlighting. This can be achieved by embedding the code within <pre> tags and applying a CSS style that highlights the code. This will make the code more readable and visually appealing for users.

echo '<pre style="background-color: #f4f4f4; padding: 10px; border: 1px solid #ddd;">';
echo htmlspecialchars($your_php_code_here);
echo '</pre>';