Well, if you're publicly traded company, each of your announcements will become public as you have to publish your reports online. These news about Remedy doesn't come from announcements they make on press releases, social media or whatever, these are things they're obligated to share to their investors
If you think about it, it's hard to have quarterly meetings with your investors by saying "we spent X money on one of our unnannounced projects, but we can't say on which, as you know it's not announced yet" and convincing people to invest in them if they can't even read basic stuff how company is spending their finances. Larger publishers doesn't have that problem as they have a huge stream of projects and they can refer to them in their financial reports by segregating them to publishing labels, but with companies like Remedy or CDP Red, their project input is significantly smaller and you need to have something you can refer to in your financial reports so they could associate data with these codenames without compromising the fact these projects aren't "officially" announced yet. That's why they're using worktitles