fieldByName('age'); echo $age;In this example, we are creating a new FieldList object that contains three fields - a TextField, NumericField, and EmailField. We are then using the fieldByName method to access the 'age' field specifically and storing it in a variable called $age. We then print out the $age variable to the screen. It can be determined that the package/library being used in this example is likely the SilverStripe Framework because of the use of the FieldList class and its associated fields.