  The ALICE ITS3 is a novel vertex detector replacing the innermost layers of
ITS2 during LS3. Composed of three truly cylindrical layers of wafer-sized 65
nm stitched Monolithic Active Pixel Sensors, ITS3 provides high-resolution
tracking of charged particles generated in heavy-ion collisions. This
contribution presents an overview of the ITS3 detector, highlighting its design
features, integration and cooling, and the ongoing development towards the
final sensor. Furthermore, the paper introduces the off-detector service
electronics, which play an essential role in the readout, control, and power
supply of the detector.
