The original version of the demo app written by agg23, as demoed on his Twitter https://twitter.com/iam_agg/status/1723042566235455636, displayed Rick Astley and played an mp3 of "Never Gonna Give You Up", but I did not have an interest in compiling an mp3 library and did want to test if I could generate audio such as a 200 hz tone, so.
Anyway check out the pretty blue snow pattern that the beta RISCV core displays before you load an app. It's not intentional but I'm trying to convince agg to keep it