The chime comes from Skype on Windows Phone 8.1 devices such as the Nokia Lumia line, Microsoft's mobile system from the mid 2010s. As Lumias disappeared from everyday use, recordings of their system sounds were saved and shared in soundboard collections and short videos. Creators now reuse the startup tone as a shorthand for an era of colourful tiles, live hubs and early mobile video calls, which is why it still appears in nostalgia posts and tech memes long after the platform faded.