Government works generally are automatically not subject to copyright under 17 U.S.C. § 105, available at https://www.law.cornell.edu/uscode/text/17/105

However, that doesn't necessarily mean they're public domain. Trademark law still applies, for example.

Additionally, not everything the government uses, even exclusively, was produced or is owned by the government. Often, government contracts allow the contractor to retain control and ownership of the intellectual property. The government may also have copyright transferred to it and retain that copyright. A legal issue I haven't researched is the line between a work that is a government work under work-for-hire principles, and therefore is ineligible for copyright protection, and a work for which the government contracts and for which copyright is subsequently transferred.

Before attempting to FOIA the source code of a piece of government-exclusive software, I would first FOIA all government contracts for the creation of that software. Then you'll have something to go on when crafting the FOIA request you really want.

proper term is "imaginary property". other than that, like this comment.

Just had a look at what the IRS has to say about open-source software:

https://www.irs.gov/privacy-disclosure/use-of-federal-tax-in...

lots of vague stuff, but looking at the Google result, I noticed some differences. Ah, the meta description of the page reads:

Open source software, while it can be useful in many instances and appear to be cost effective, may present a security risk because open source developers don’t typically follow security best practices when developing their software.

Well, there ya have it! :D

They have publications:

https://www.irs.gov/e-file-providers/modernized-e-file-mef-u...

Intuit and HR Block lobby against it every year, and the IRS continues to threaten to do it.

It is an unclassified federally-funded document -- as I understand things, it is therefore in the public domain.

Because many eyes often make bugs shallow, there is a pretty good chance that a public release of the code will find errors that both find funds that are owed to the government and exonerate people who have been incorrectly billed.

What better purpose for the American Fuzzy Lop?

This can’t possibly be true, in general. Work products produced by a contractor from a federally-funded project are not automatically in the public domain. Government-held, unclassified data can be sensitive, proprietary, confidential, or contain private information about citizens. None of this is public domain.

The lobbying push from companies that would rather it wasn't (because it could erode their market position by lowering the entry bar for competitors) is stronger than any current push in the other direction, would be my guess.