Hmmm, I am buying mine through fidelity - but its not a retirement account.
If you have the same options as me - if you go under "News and Research" == Fixed income == new issues (this one is midway down the page in a line of other stuff) scroll down and the first option is treasury. I see this. first is a 4 week then 8 week, then it looks like a 5 year note. There expected yield is way off always - no idea why. If you go to treasury direct you can see all the most recent auction results (click on the auction results tab)
https://www.treasurydirect.gov/auctions/upcoming/
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