According to Teslarati, a Tesla-watcher news site, a Boring Company equipment was spotted at Tesla's under-construction giga factory in Austin Tesla. After a spat with Californian State authorities, Elon Musk had earlier announced plans to move the headquarters of The Boring Company to Texas, not far away the site of the Tesla Giga factory being built there.

Some news had surfaces about Tesla's plans to use tunnels to move its spare parts from nearby facilities to Tesla's factory. It is not clear if the Boring Company equipment is there to that end or just some ancillary equipment  like a grout mixer which was needed for the construction of the factory.

Footage taken by YouTuber Jeff Roberts, who has been documenting Tesla's Gigafactory construction day by day. I watched the video and I could not see the equipment bu Teslarati says it "appeared to be a fuel or water tank with the Boring Company’s now-unmistakable logo" on it...

https://www.teslarati.com/tesla-gigafactory-texas-boring-company-equipment-video/