What is the purpose of a low-pass filter used at the output of a digital-to-analog converter?

When a digital-to-analog converter (DAC) reconstructs an analog signal from discrete digital samples, the raw output isn't perfectly smooth. It resembles a 'staircase' of discrete voltage steps, which inherently generates unwanted high-frequency harmonics and spurious sampling artifacts (images). To smooth out this staircase waveform and produce a clean, continuous analog signal, a low-pass filter (often called a reconstruction filter) is placed at the output. This filter strips away the high-frequency artifacts while allowing the desired baseband analog signal to pass through unhindered.