Opensource.com - https://opensource.com/article/18/6/sound-themes-linux
Like all modern operating systems, Linux has a set of specifications for sound themes. Sound themes are sets of similar sounds coordinated into themes that sound good together. They signal events such as switching to a different workspace, opening a new application, plugging and unplugging hardware, and alerting you when your battery is low or fully charged. The sounds that play is determined by which themes you have installed and which ones you’re currently using.