This video was made in 1981. Tektronix manufactured their own cathode ray tubes (CRTs) for oscilloscopes (and later, computer terminals and displays) from the early 1950s until 1996, when flat panel displays on digital storage oscilloscopes supplanted analogue technology in their product line. By 1981, Tektronix had migrated completely to ceramic funnels for their CRTs, a technology they pioneered.
For the reason why “butterfingers” is career-limiting in CRT manufacturing, see the post here from 2022-10-07, “Imploding CRTs at Tektronix”. A later film, showing high-volume production of CRTs, is in the 2023-05-11 post, “From 1983—Volume Production of High-Precision Cathode Ray Tubes at Tektronix”.