src/Web/ErrorHandler.php
public function isCoreFile($file)
    {
        $corePath = Reaction::getAlias('@reaction');
        return $file === null || strpos(realpath($file), $corePath . DIRECTORY_SEPARATOR) === 0;
    }
public function isCoreFile($file)
    {
        $corePath = Reaction::getAlias('@reaction');
        return $file === null || strpos(realpath($file), $corePath . DIRECTORY_SEPARATOR) === 0;
    }
Determines whether given name of the file belongs to the framework.
@param string $file name to be checked.
@return bool whether given name of the file belongs to the framework.