There are techs to unlock colonisation of different kinds of worlds, starting with 60% habitable ones (from my species' perspective). I understand what this means for colonising with my primary species. But what about other species? Can they only be used to colonise their favourite world type, or do other worlds also get unlocked for them with tech? What about robots? Logically a robot colonist shouldn't care about habitability ratings, but I don't know if there any tech-based restrictions. Tomb worlds seem to be a special borderline case, as they're 0% habitable but still have a surface view.
Also, am I correct in understanding that even robots can't colonise Barren, Frozen, Toxic and Molten worlds? (Seems a bit unfair with Barren at least - I don't see why robots should care if the planet has no atmosphere.)