It's difficult to know when to use the Stack Exchange "answer" field for an inconclusive answer, but after a review of the IRS's website, I don't see much sign of this, particularly for the 1f code on that form, but really, for anything. The most prominent source of structured data from the IRS that I found is the Tax Stats section, which isn't what you're looking for.
There's an extensive section for "e-file providers", including some PDF docs that articulate valid code values, but nothing machine readable that I see. Maybe they make that sort of stuff available to approved e-file providers?
Note that the 1099 form instructions you referenced are also available as HTML as well as PDF, although you'd still have to scrape free text.
This seems like a case where you are best off asking the IRS directly, both to get an authoritative answer, as well as to register public interest in more structured data from them. Also, while I know that tech folks are often inclined to simply fill out a form or send an email, this may be a case where a phone call would pay off. Sometimes (but definitely not always), a real-time human interaction helps cut to the chase, and can result in social referrals to people with better information or more access than you can find by impersonal electronic means. However, the IRS has not been very forthcoming with publishing machine readable data thus far.