FreeBSD creates a branch off current very close to a major release. So work for a new major release happens on current. At some point current blocks new feature

FreeBSD creates a branch off current very close to a major release. So work for a new major release happens on current. At some point current blocks new features and focusses on fixing bugs. Then a branch for the major version is created and current can work on the next major release. After that, minor releases mostly contain backported material.