public void releaseNotes(Action<? super ReleaseNotes> action) {
        action.execute(releaseNotes);
    }

    public UserManual getUserManual() {
        return userManual;
    }

    public void userManual(Action<? super UserManual> action) {
        action.execute(userManual);
    }

    public DslReference getDslReference() {
        return dslReference;
    }

        });

        extension.userManual(userManual -> {
            userManual.getRoot().convention(extension.getSourceRoot().dir("userguide"));
            userManual.getStagingRoot().convention(extension.getStagingRoot().dir("usermanual"));
            // TODO: These should be generated too
            userManual.getSnippets().convention(layout.getProjectDirectory().dir("src/snippets"));