What are the potential pitfalls of using non-masked quotation marks in HEREDOC strings in PHP?

Using non-masked quotation marks in HEREDOC strings in PHP can lead to syntax errors or unexpected behavior if the quotation marks are not properly escaped. To avoid this issue, it is recommended to use masked quotation marks within the HEREDOC string to ensure proper parsing.

// Using masked quotation marks in HEREDOC string
$variable = <<<EOD
This is a HEREDOC string with "masked" quotation marks.
EOD;