Who's still using CVBS, and for what?
NTSC waveform monitors and vectorscopes are amazing instruments. For example, only with them you can see the true color (pun intended) of the STMPT color bars on TVs - the iconic staircase waveform [0] and its corresponding curve on the vectorscope [1]. They are how the color bars were intended to be viewed.
During my recent hunt for test equipment, I was still able to find a lot of waveform monitors and vectorscopes in usable conditions. Unfortunately, I couldn't find any reason to buy one - it will be a complete waste of money and room space since these instruments have became totally useless with zero utility. You don't even have a signal to probe anymore, unlike a vintage computer or an oscilloscope which can still be used and even serve a practical need... To think about it, they'll continue to be stored in an abandoned warehouse collecting dust and rust indefinitely until someone sends them to a metal scrapyard.
It's really sad.
[0] https://i.stack.imgur.com/cIQVf.png
[1] https://www.danalee.ca/ttt/images/7/vectorscope_bars_big.jpg
Anyway, I noticed something about the parent comment that I missed earlier -- "for timing purposes". Huh, like I guess the concept of genlock probably still exists, and they're probably passing around a test pattern or black frame or something just as a common sync reference signal?
(For similar reasons, a lot of telecom gear uses a 1.544Mbps "all ones T1" signal for sync, even if there isn't a real T1 circuit anywhere.)