Tesla has added a new Megaphone mode in the audio options of the mandated external speakers that are used to raise awareness among pedestrians about a Tesla approaching at low speed. The Megaphone option is in addition to the Boombox mode that was received with the big holiday update last year, and could play pre-recorded audio via that same speaker alert system.
https://www.notebookcheck.net/You-can-now-use-your-Tesla-as-a-megaphone-to-alert-pedestrians-in-real-time.588743.0.html