We are haunted by dead futures that cannot come to pass.
If anyone wanted to keep track at home, 3Whysmen summarized the timeline neatly in a post on the subreddit:
This is from X7, which wasn't Disco Elysium 2. Disco Elysium 2 was Y12, Y12 was cancelled when Kurvitz, Hindpere and Rostov were fired. X7 development began after that firing and ended after the mass firing where Tuulik was let go.
X7 was supposed to be fairly far in production when it was cancelled and supposedly had a playable alpha build that was circulating on a USB at some point. Where as the cancelled sequel Y12 didn't seem very far into production when it was cancelled.
Also, that this surfaces when Tuulik's NDA expires and he gets to start working on whatever it is they're working on at in Summer Eternal... let's just say that there are no such things as bad coincidences.
For what it's worth, I'm not sure how I feel about what's presented here: a lot of it reeks of sequelitis and a "more for the sake of more" narrative/design philosophy that... I feel kinda misses the point of DE's elegant mechanical simplicity and how those mechanics reinforced the narrative being told. Of course, we can never actually know if that was actually the case, since the moneymen strangled this in the crib.
But maybe it's better that way- the Disco Elysium sequel in our mind will always be the best one.
Edit: Derp didn't realise CredibleBattery also posted the link as well but I guess I'll just leave this post up cos I don't want to delete and type everything again 
As like a corporate spin-off/side-story to Disco Elysium this feels pretty inspired. Within the corporate structure that games seemingly need to be made within, you can't really hope for them to make something as inspired as the original just a second time. And I'd much rather play as some kids running from the law than as another cop/authority character again, like that already shows more reflection than any of the other "spiritual successors" we've seen so far. This being more of a "on the road" story, controlling two characters with different skills and thoughts, the locust City concept, the concept art and all that seem genuinely inspired too. Interesting to get such a close look into their design docs too, wonder if someone is just gonna leak that entire thing at some point.
Sure is telling though that even this, which already has all the "this is the stuff we could cut if we have to hit some deadline" built in, was still somehow too much to be allowed to be made.
Summer Eternal does have some of the key creatives(that we know of) from this project, so there's hope that some of the inspired concepts will carry over to what they make.