You can get additional information about files and folders by displaying their Properties dialog. To do so, select a file and either choose the Properties menu-item in the File menu, or right-click on the item and choose Properties in the popup menu.
If you choose the Properties menu-item when no files or folders are selected, information about the current directory is displayed.
If you choose the Properties menu-item on the root folder of the GMail Drive, a Property Page will be shown with general information about the GMail volume and account.