The lore revealed by the most recent Miliastra Wonderland outfit sets:

1. If you played 6.7, you would know that it talks about the idea of disguising a world or moon to make it look empty in order to deceive the Abyss and any hostile forces.

According to this lore, the 31st planet Octavia visited in the Genshin universe had the same idea:

Early in her travels, Octavia arrived at Planet #31, which looked barren from above, though “parts of its surface bore the marks of human work.”

What set them apart was that they lived clustered, nearly obsessively, in a hundred cities, combining giant canvases and living plants to “raise umbrellas”

over every building, trying to disguise each city as a forest or a stretch of empty hills…

This strange phenomenon traced back to a single astronomer’s warning.

With a simple but effective telescope, he had captured the process of many stars being devoured by an “unnameable pitch-blackness,”

compiled his evidence in painstaking detail, and then spent thirty years lobbying every faction he could reach, convincing them all to undertake this civilization-scale act of disguise.

“Fighting a thing like that is a fool’s hope. We have to hide, buy ourselves time, lay down a technological foundation firm enough to matter…”

2. There was a group on Planet #31 that wanted to reach out to the wider universe and reveal the world’s disguise:

The stars ran deep. No sooner had the civilization-scale act of hiding begun than certain fanatics began scheming,

trying to signal the skies, willing to drag all of humanity down with them into their lives, bereft of hope.

3. Geography of Planet #503:

The climate of Planet #503, the “Ocean World,” is a peculiar one, seemingly summer year-round, and no cooler far inland than it is by the sea.

On top of that, mountains on the planet don’t reach great heights, so even at the summit, you’re spared the sting of biting wind.

4. Octavia has friends whom she either visited different worlds with or met on other worlds:

When Octavia and her friends from the Academy Planet went hiking there, she habitually bundled up the two young researchers against the cold, only for them to end up sweltering at the summit.