IGMP encapsulation in PPPoE

In fact I'm quite familiar with PPP protocol with bells and whistles alone, but I'm a bit puzzled what is the thing with IGMP (and VDSL specifics) here. Does this mean that that not all the traffic over the VDSL lines is encapsulated, but just some authentication data?

And then of course the IPTV content apparently should as well, but Orbi is not doing that(?)

So I'm just saying that I don't really know how VDSL lines usually utilize protocols and wonder if someone could tell right away. Maybe even Netgear could make German Telekom IPTV finally work as well if here's something. Looks like there are other people out there hoping Orbis to work with it.