Each row says what is behind its code before you follow it. Article — the entry is written and has its own page. Brief — no page of its own yet; the link leads to whatever holds it. Register row — the code exists and the entry is not written. The register is wider than the library of written entries, and always will be; this line is here so the interface does not pass one off as the other.
The Library admits the luxury brands of a group and not the group’s whole portfolio. What follows is what it holds from this one — each with its own permanent code and its own entry. Everything else the group operates is outside the Library’s scope, not beneath its notice.