What this RC element does on the coil
The 3RT5956-1CF00 is a surge suppressor built as an RC element — a resistor-capacitor snubber wired across the contactor coil to damp the voltage spike when the coil de-energises. It fits the SIRIUS overload relay size S6, so if you are commissioning a panel with an S6 contactor or starter combination, this is the matched suppressor for that frame.
That means you can spec it into a new BOM without worrying about an imminent EOL, and the supply channel is the standard Siemens distribution route. No stock-holding claim here — the page is the RFQ starting point.