Windows 10 Build 10074, released in April 2015, introduced a refreshed, "softer" set of default system sounds and a new horizontal volume control to align with a modernized, flat design language. This build featured unique "intermediary" audio files, often referred to as "Gumball," which were subsequently tweaked in later versions. For more details, visit Windows Insider Blog SoundCloud Windows 10 Build 10074 Sounds - Stream Gumball - SoundCloud
If you are running this specific build or a modded version designed to mimic it, you can find the raw audio files locally: windows 10 build 10074 sounds