The rlabel lines define labels in the circuit. These lines contain the word rlabel followed by the layer of material that the label may be attached to or space.
Following the layer are the coordinates of the lower left and upper right corners of the label. This implies that the label may be a rectangle, but most labels use the same coordinate for both corners and thus become points. Since Carafe can only represent labels as points, it will use the center of rectangular labels as the location of the label.
After the coordinates is an integer indicating the position or orientation of the label. This number is ignored by Carafe.
Finally the actual text for the label is given as any string of characters not including the newline. Carafe adds the restriction of no intervening white space characters in the text.