I'm designing a keyboard and I want to be able to daisy chain another USB device through it. I have a Drop ALT that does this and I really like it. It has two USB C ports and you can connect either one to the computer and use the other as a pass through. It uses a USB2422 as the hub and I've read the data sheet several times but I can't figure out how it's working. The USB2422 has one upstream port and two downstream. I thought the upstream would go to the computer but then why doesn't it matter which port you use?
Edit to add pictures.