Surprisingly, an empty string is a valid token. This type is used for tokens that must have at least one character in them. This type is used for non-null tokens that have a required 'name' attribute. This type is used for non-null tokens that have and optional 'custom1' and 'custom2' attributes, the value of which must be a cid. This type is used for non-null tokens that have a required 'type' attribute.