Roomba target

DUST

Think of what settles on shelves over time and gets sucked up by a robotic vacuum—it’s not dirt or debris, but something finer.

A Roomba is a robotic vacuum cleaner, so its main job is to clean up dust from floors. The clue plays on this by calling dust the "target" of the Roomba—what it seeks out and removes. It’s a straightforward reference to the device’s purpose, with no hidden wordplay or tricks. The answer is simply what the Roomba is designed to eliminate.