Thought this would be the best place to share, I think I've got to the bottom of what's most likely happening with the Italian Rai services on the 5°W multistreams, what with the recent Symbol rate and stream changes.
As part of the Italian move to MPEG4 away from MPEG2 SD (as has also been happening with Tivùsat on 13°E), the Rai are reorganising their DVB-T multiplexes, which are largely delivered to the transmitter sites in Italy via the multistreams on 5°W. DVB-T2 is supposedly being brought in on a non-mandatory basis from 2023, but for now it's just a case of sticking with DVB-T but clearing 700MHz which means Italian DTT condensing its many multiplexes down into a smaller space.
For Rai, their plan seems to be replacing the many individual "Rai Mux 1" multiplexes in each region, with 11 multi-region "Rai Mux R" multiplexes, each containing three versions of Rai 3 -
RAI Mux R - Wikipedia
Until now, the method of transport for Rai Mux 1 via the multistreams has been to have a single stream carrying the national Rai 1, Rai 2 and Rai News 24 services, and multiple individual streams carrying each of most of the Rai 3 TGR regions.
The DTT multiplex switchover has started in the Valle d'Aosta and Sardinia, and sure enough -
11013V Stream 3 - is now carrying the Liguria - Sardegna - Toscana version of Rai Mux R (labelled R8 on that Wikipedia page).
11179V Stream 6 - is now carrying the geographically slightly bizarre FVG - Bis (Slovenian language opt-out version for FVG) - Valle d'Aosta version of Rai Mux R (labelled R7 on that Wikipedia page).
Both of these transponders have changed symbol rate in the last few months to 35300, which gives space for three of these new 20Mbps streams, plus extra wiggle room for moving stuff about. If this change eventually happens across all four of Rai's multistream transponders, there's room for 10 of the 11 new "R" multiplexes plus the two national multiplexes (currently on 11179V).
The two new R multiplexes are currently MPEG2 SD, but as far as I can see from a bit of reading, the plan is that these eventually change to MPEG4 HD to replace the existing Rai 1, 2 and 3 HD, with Rai 3 HD becoming regionalised.
My guess at the missing one of the 11 that won't make it to sat is R2 with the German language Rai Südtirol, Trento and Bolzano, which has never been on the multistreams before. However, that's also been the case with the Aosta/FVG ones which we have now gained! The alternative would be that they split them like the legacy versions, with just one Rai 1/2/24 stream to share, which would mean they can fit all of them.