How can predefined constants be utilized in PHP to access file modification information?

Predefined constants in PHP, such as `filemtime()` and `filectime()`, can be utilized to access file modification information. These constants allow you to retrieve the timestamp of when a file was last modified or when its inode was last changed. By using these predefined constants, you can easily retrieve and display file modification information in your PHP code.

$filename = 'example.txt';

// Get the timestamp when the file was last modified
$lastModified = filemtime($filename);

// Get the timestamp when the file's inode was last changed
$lastInodeChange = filectime($filename);

echo "File last modified: " . date('Y-m-d H:i:s', $lastModified) . "<br>";
echo "File last inode change: " . date('Y-m-d H:i:s', $lastInodeChange);