Question about Internet recovery March 23, 2023; See Description for detail of question

Question about Internet recovery March 23, 2023: During recent crazy storms on Tues March 22, 2023, my Internet (San Fran Bay Area) went out. It remained out until Wed March 22. An Xfinity truck pulled up to the XF box on a nearby corner, but after the driver was out of the truck for a short time, he pulled away. He came back after more than one hour. He went up in the bucket truck, and had some device that looked from a distance like a portable generator, and he pulled a cord as one will to start a fuel powered generator. He left this red box on top of the Xfinity box and left. After quite some time, more than a couple of hours I think, the red box was still there, but my Internet was restored. I don't know when the red box was removed but it's gone now. Please explain.