The intention is to make it possible for everybody to make one's own versions of some files (e.g. corrections to header files), and therefore, the default protections will not prevent it. However, such modifications should only go to side branches, so that the main and hp10 branch types are locked.
We shall put there both HP-UX 10.20 and HP-UX 11 versions. The /main branch is dedicated by default to HP-UX 11, and when there are differences, HP-UX 10.20 software will be found under an hp10 branch.