I took the repeating extragalactic radio signal that Chime telescope detected from 1500 milions years light distance, and I got lower its speed and frequency to listen the sound more in detail. You can perceive a kind of arpeggio, or scale going down.
By my view, this gradation of tones are likely natural , like the rebounds of a ball when it falls only by the force of gravity. If it had a technological origin, the musical sounds wouldn't draw such a gradual scale or arpeggio.