If Software Is Funded from a Public Source, Its Code Should Be Open Source
Government scientist here.IANAL, but my understanding is that all software written by US government civil servants is in the public domain. It cannot be copyrighted or otherwise licensed (although the government can patent things). This does not necessarily mean that it is available to the public, as noted in the other comments; it may be classified, considered For Official Use Only, or restricted from release by ITAR regulations.Barring any of those cases, you should be able to get a copy by filing a FOIA request. The problem with FOIA requests is that you have to know specifically what to request, usually by name. Obviously, it can be hard to put your finger on exactly what software you are requesting.The bigger problem, though, is that much of the US government just isn't technically set up to release software (as opposed to documents). Setting up a git repository, in the DoD, is an utter nightmare. Every single patch has to be pushed through a public release process that can take weeks or months and involves review by as many as ten to fifteen different offices, few if any of which even know anything about software. If you're setting up your own server, getting the server itself approved and provisioned can be an exercise in bureaucratic frustration, and can take literally years to accomplish.Those of us writing software very often want it to get out there. But the structure of the organization makes that excruciatingly difficult.