This lens, a Nikkor 80-200 AIS, has some curved lines that are color coded to match the aperture ring. Originally I thought this was for focusing but playing around with it does not make it seem like that is.
Any idea what they might be indicating?
The aperture ring is engraved with f-numbers duplicated; the duplicates are color coded the same. The lines you are asking about are also paired, same color. The idea is to graphically display the zone of depth-of-field. As an example, you focus on an object at 10 meters (32 feet) as indicated by the thick center white line. Setting the aperture at f/8 (yellow), the span of the depth of field lies between the two yellow (color matching) lines.
The unpaired red line is the infrared focal point, if you're using infrared film.