wp-includes/pomo/streams.php:313$filename public function __construct( $filename ) { parent::__construct(); $this->_str = file_get_contents( $filename ); if ( false === $this->_str ) { return; } $this->_pos = 0; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/pomo/streams.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.