The sound comes from Age of Empires II, the real-time strategy game first released in 1999, where villagers are trained at the Town Center and then gather resources and construct buildings. Players hear it constantly during a match, so it became shorthand for starting work, growing an economy and building an army. As gameplay clips and strategy memes spread online, creators began lifting the short cue for edits outside the game, using it whenever something new appears on screen. Its familiarity among RTS fans keeps it useful decades later.