Boring a stationary part - GIF

[Toolmaker51]

I would like to know the application.......and the machine!

The video too brief 'down hole' to be accurately guessed, could be engine cylinder, main bearings, yoke of construction machinery, any of a variety of pumps, infinite range. Near certainly too big or far to haul indoors to a jobber. Can't get a good pause on the label of the rotating head, but one commercial example is called 'Rottler'. Over time many manufacturers, but always called a portable boring bar. Everything is included to mount in place, locate centerline, affix cutters and proceed.