I think it's at least implied the collective is the (majority of) changed people just at a future/alternate point in the timeline. This is part of the reason the anchors are needed during the ascension process, to connect to the Collectives spacetime like you would with a rift.

From what's presented in the game, my understanding is that the Travellers go back in time to target specific minds who wouldn't normally become part of the collective (orphans) that have valuable abilities or data. These are then basically stripped of all free will and humanity and forcibly become part of the collective on ascension. Normally after the change completes unmerged entities are incompatible with other entities so we time travel to get them before they change and become incompatible (corrupt).

The Travellers themselves are probably (I'm not 100% sure if this is confirmed or not) just lumps of biomass in the temporal shells with a stripped back essence put in them. This explains why we have to download essences from other phylacteries instead of ripping them off the bodies. We ourselves are the phylactery. When the phylactery is full we're effectively merged in the same way the collective or Eliza are. Traveller Essences have so little identity though that they contribute very little to the gestalt entity that emerges if the phylactery is too full for too long, unless they're able to gain a personality via long operation or interference (like the pathfinder and to some extent the traveller does).

Thematically the collective seems to represent the worst excesses of Marxist-Leninist utopian ideology, so it's certainly not a good time for the people subsumed by it (makes sense with a Polish dev). A lot of the other options the game presents are a pick your poison kind of deal though.

But what pecisely is these Collective: A collection of essences (souls) of selected people living in an A.I. , or what ?

Цитата допису Molesworth.Houghton:

But what pecisely is these Collective: A collection of essences (souls) of selected people living in an A.I. , or what ?

I think its their minds in digital form uploaded to some kind of collective server. Thats how I took it, no bodies just consciousness