Extender from case to motherboard component (BitWit White Build)

Solution
Here's a screenshot of the video right at 6:55. I added a couple text descriptions, about the only component I can think of might be the fan hub. It's got several fan cables connected to it. If so, it also comes with the case. It's supposed to be connected to the pwm fan header (cpu_fan) on the motherboard. Then additional fans plug into it and are speed controlled so your case fans spin faster and slower with the cpu fan. If the system is under load and running hotter all the fans (cpu cooler and case fans) run faster, as everything cools down all the fans can run slower and quieter.
f325e197fdc5451699c8499fce2136ed.png
I'm not sure which part exactly, around that time mark they were strapping the cables to the back of the motherboard tray using the included velcro straps. That's part of the case and allows people to route the wires behind the motherboard and secure them in various bundles. The only other component they used was an extension 24pin cable for power to the motherboard pre-sleeved in white.

If you're referring to the inside of the case where the motherboard, cpu cooler and gpu are visible, at one point they had the case turned in the camera view and on the right side of the screen was the psu cover. That's also included with the case. Those are about the only things I can think of that were cable management related. Not all cases come with a psu cover (if that's the part you meant) and not all cases are set up to use one. They come with the case and there are a few cases which have psu covers.
 
Here's a screenshot of the video right at 6:55. I added a couple text descriptions, about the only component I can think of might be the fan hub. It's got several fan cables connected to it. If so, it also comes with the case. It's supposed to be connected to the pwm fan header (cpu_fan) on the motherboard. Then additional fans plug into it and are speed controlled so your case fans spin faster and slower with the cpu fan. If the system is under load and running hotter all the fans (cpu cooler and case fans) run faster, as everything cools down all the fans can run slower and quieter.
f325e197fdc5451699c8499fce2136ed.png
 
Solution