What are the limitations of using the include function to insert a favicon in PHP?

Using the include function to insert a favicon in PHP is not recommended because the favicon is a link tag that belongs in the head section of an HTML document. Instead, you should directly add the favicon link tag in the head section of your HTML document.

<!DOCTYPE html>
<html>
<head>
    <title>Your Page Title</title>
    <link rel="icon" href="favicon.ico" type="image/x-icon">
</head>
<body>
    <!-- Your page content here -->
</body>
</html>