wp-includes/pomo/streams.php:309Reads the contents of the file in the beginning.
class POMO_CachedFileReader extends POMO_StringReader { /** * PHP5 constructor. */ public function __construct( $filename ) { parent::__construct(); $this->_str = file_get_contents( $filename ); if ( false === $this->_str ) { return; } $this->_pos = 0; } /** * PHP4 constructor. * * @deprecated 5.4.0 Use __construct() instead. * * @see POMO_CachedFileReader::__construct() */ public function POMO_CachedFileReader( $filename ) { _deprecated_constructor( self::class, '5.4.0', static::class ); self::__construct( $filename ); } }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.