Shortly after releasing Teensy 3.6 (in 2016), we were buying this product and removing the 2 cables.
https://www.cablewholesale.com/products/usb-firewire/usb-2.0-cables/product-31u1-02408.php
It has a PDF on their website. I'll also attach a copy to this message, in case it disappears in the future and people later find this message by search. The connector is documented only as "Beige Molded PVC". Unfortunately that is all the info I have available.
I can't speak for Cable Wholesale, but my impression was each batch we received differed from all the prior ones, so I wouldn't put a lot of faith in that drawing's specific details.
We got tired of removing the screws. One of the batches had locktite on the screw threads... which was *not* fun. Eventually we reached out to a few Chinese contract manufacturers and sent them Cable Wholesale's drawing and asked if we could buy just the cable without the PC mounting bracket. Of course the answer was yes. It's always difficult to interpret details from vendor emails, especially those who aren't native English speaking, but my impression was they found available inventory rather than making it themselves.
Nearly all the communication we've had with them since has revolved around what type of mounting screws are included and whether they come pre-installed on the cable or in a separate bag. Everything else like the actual connector spec has been a matter of "ain't broke, don't fix".
This probably isn't the highly detailed answer you wanted. But the reality is Teensy 3.6 in 2016 and then Teensy 4.1 in 2020 had a design goal to be able to work with the internal USB2 cables used for PCs, rather than requiring a custom cable. Every host cable we've ever sold was just a commodity PC cable we purchased in bulk. That fairly generic Cable Wholesale drawing really is the best info available.