Does the spread of "immigrant" population among european countries indicate more a larger immigration or more regional segregation (whether forced or spontaneous) of immigrant populations?
A mix of both, higher overall level of migration especially in those countries with extrametropolitan territories where former colonial populations can more easily relocate to the mainland (compared to formal independence and need to immigrate in OTL) and less emphasis on assimilating those people into the main ethnicity.
Interesting to see Rusyns considered as Galicians
The Galician consciousness is more developed due to prolonged Habsburg rule (with their support of Ruthenian
ness to set them apart from Ukrainians) and natural differences between them and mainstream Dnieper Ukrainians (Greek Catholicism, Latin-script language [yep] ...) Galicianism ranges from "Galician is a way to be Ukrainian, and we must be the vanguard that leads the country!" to "Galicia is a nation opressed by Kiev and we must strive for her independence!"
These baltics... I've seen enough maps of IRL spread of russians to know germans probably are as numerous there if not more.
Germans are something between 15-25%, with a further 10-20% being Yiddish-speaking Askhenazi Jews.
The inclusion of circassians as a separate groups is interesting.
They have disproportionate political-military influence in the Ottoman Empire despite what their numbers suggest.
Ukraine seems fascinating ITTL, would love to see more detail, although we've already seen a bit of it.
It's had a convoluted history, part of which we've seen glimpses, but as this map suggests the Galician Question is still a hot toppic on Ukrainian politics. And then add Germans, Jews, Russians, Romanians, Tatars and even Greeks into the mix.
Also wondering how russia deals with so many caucasians and central asians.
Mostly by the sheer pressure of more than 260 million Russians, which form pluralities if not majorities in most decent-sized cities.
I'd have expected more immigrant groups in Britain and Portugal, interesting.
In the UK they are from so varied ethnic groups that they don't form pixel-sized pluralities or by 2nd-3rd generation they have assimilated into a British identity (contentrated on the Southeast, industrial English cities and major Irish and Scotish cities), reflecting the "immigrational background".
Portugal has remained an emigrant source instead, with 1 in 4 Portuguese-born living abroad in either Brazil, Angola or Mozambique.