Plain English Meaning
This is the second of two ILS approaches that both lead to Runway 28 at the same airport. The '2' is just a label to tell them apart on the chart.
Full Definition
An instrument approach chart title indicating the second distinct ILS (Instrument Landing System) procedure published for Runway 28 at a given airport. The number '2' is a sequencing identifier used when more than one approach of the same type serves the same runway, typically because the procedures differ in some operationally significant way such as required equipment, minimums, missed approach, or feeder routes.