Here you can view the metadata definitions that are created on the web site and has the option “Field is insertable in portlets" activated. These can be inserted into text portlets e.g. to insert when the page was created. First type the desired text and the click on the medata option and select the metadata to be inserted, in this case “Date Created".
When fetching a metadata definition the text will be dimmed. It is not possible to edit this value manually since it is being fetched automatically.