The VM reaches the internet through a relay. The default is Mercury Workshop's public Wisp server, which sees your VM's traffic. Leave the field empty to use it. To run your own, use npx -y -p @mercuryworkshop/wisp-js@0.5.0 wisp-js-server and enter wisp://localhost:5001/.
npx -y -p @mercuryworkshop/wisp-js@0.5.0 wisp-js-server
wisp://localhost:5001/
TabShell can't run from a file you double-clicked. Double-click start.command in the TabShell folder instead, and it opens in your browser.
Every file, installed package and running program on it is deleted, and it starts again as a fresh install. This can't be undone.