Elon Musk Sells Flamethrowers Online to Fund Tunnels

Elon Musk promoted a flamethrower on Instagram, humorously advising against buying it unless for fun. Despite this, the Boring Company sold over 10,000 units, generating $5 million. The funds will support Musk's underground transportation projects, with a test tunnel already underway in Los Angeles.

What ambitious project is Musk funding with the flamethrower sales?

Where did the Boring Company begin digging a test tunnel?