#3 appears to be a catch-all for "we haven't decided our policy is yet, and publishing the source code early, while we're still considering the options, forces

#3 appears to be a catch-all for "we haven't decided our policy is yet, and publishing the source code early, while we're still considering the options, forces us to make a premature public statement." For example, suppose the government was going to establish a new video codec for its own video releases (ie, suppose that Dirac doesn't exist). There are several options: create a new and unencumbered license, negotiate a license for an existing system, or purchase the patent right from the patent holder. The final choice depends on the cost to develop a new codec, the success of that codec, and the cost of buying or licensing the patent(s). The government can explore all of these at the same time, eg, set up a group to develop a new codec while negotiating with various rights-holders. The new codec might be finished while the negotiating is ongoing. The government knows how well it fits their goals, but the rights-holders do not. This gives a negotiation advantage to the government. On the other hand, if the completed codec were immediately published, that advantage disappears. The rights-holders might decide to raise their prices after seeing just how bad the new codec is, which makes the government goal of more open access to their video archives more expensive. Thus, the government could rightly "judge the public interest not to be served by publishing [their] own software", even if, after the negotiations have completed, the software will be published.