CloudFiles Content Library tab can be used to explore any supported external storage from within Salesforce. To use this, just select CloudFiles app from the app launcher & click the "Content Library" tab
One of the primary usage of Content library is to get metadata values for files & folders to be used in flow actions and apex. Examples of metadata values are - file/folder id, library, drive id etc.
To get the metadata values, simply click on the dropdown icon in far right on the item row. Click "View Metadata". You can also click the copy icon to quickly copy the values to clipboard