The clip is an 11 second sound effect recording credited to SoundBible.com under the title soldiers marching. Stock marching recordings like this have long been used as generic military foley because a single unit marching in time is hard to capture cleanly on a film set. Online, creators reuse the same recording for history projects, army edits, reenactment videos, and strategy game content where they need believable troop movement without recording a real parade or training exercise themselves.