In another question someone ask about repair of laptop PSU. I cannot find it ATM - possibly because it was closed as about repair and off topic.
However an attached schematic to one of the answers had a sideway transformer (XFRM1 on schematic below)) surrounded by 2 caps (C1 and C2) before transformer to (I presume) lower the voltage. As far as I can tell it doesn't 'do anything' which leads me to think it may be a safety feature. What may be a purpose of it?