Note: This is a copypasta of a status update I did.
One of the things that has eluded me about USB Type C was its retention system. On Micro B it's easy to see; those little bumps on the top of the cable's connector are it (they go into divots in the device's end). But in Type C I couldn't see anything. So I chalked it up to either friction or those six metal bits on the end of the cable's connector.
It turns out it doesn't look like either. I found an exploded diagram of the cable's connector (image from https://www.tweaktown.com/news/50182/wary-cheap-usb-type-cables-fry-hardware/index.html)
And I noticed there two claw looking arms colored dark teal. That looks like a retention system. So after digging around some more, I came to this website: https://www.appliancedesign.com/articles/94953-next-generation-connectors. They have a diagram of the assembly of the cable side's connector and sure enough, there are two claw type arms on either side of the connector. And those six metal bits may or may not be metal, but they look more for structural support than for retention.
So what about the device end?
There's two flanges out on the tab that has all the pins. And to verify this was really a thing, I poked at my phone's Type C port with a staple and managed to hook onto the flange. So there you go, USB Type C's retention system.
(also I'm not sure if this was even discussed in the places where I first heard about the connector)