What's on vt10?

I've tried starting several desktops (some remote) and noticed something curious. The desktops start on vt7, then vt8 & vt9. But then for some reason, vt10 is skipped and the next desktop appears on vt11. When I switch to vt10, it appears as though it's being used for some status or error messages. Why is it here, instead of perhaps on vt6? tnx jk