This folder includes sources for Vircon32 games that are finished. Once released, these games are not expected to be updated unless serious errors are detected. Improvements to the source code or the build process should be fine, as long as the game binary is not modified.
The reason behind that is trying to ensure that every particular game offers exactly the same experience for everybody will be playing it, since all of them will have the same version. That kind of policy can also be important for certain communities, such as speedrunners or creators of mods via game patches.