What is the significance of encoding PHP and HTML files as "UTF-8 without BOM" in relation to handling Umlaut characters in PHP?

When handling Umlaut characters in PHP, it is important to encode PHP and HTML files as "UTF-8 without BOM" to ensure proper display and handling of these characters. The Byte Order Mark (BOM) can cause issues with Umlaut characters, so it is best to use UTF-8 without BOM encoding to avoid any problems.

// Set UTF-8 encoding without BOM for PHP and HTML files
header('Content-Type: text/html; charset=utf-8');