Copying here this caution comment from a user on Reddit:

Non-peer reviewed, non-replicated, rushed-looking preprint, on a topic with a long history of controversy and retractions. So don't get excited yet.

So I read the paper. Here’s a tldr about how their material apparently gains its properties.

It is hypothesized that superconductivity properties emerge from very specific strains induced in the material. Hence why most of the discovered superconductors require either to be cooled down to very low temperatures, or to be under high pressure. Both shrink the material.

What this paper claims is that they have achieved a similar effect chemically by replacing some lead ions with copper ions, which are a bit smaller (87 pm for Cu vs 133 pm for Pb). This shrinks the material by 0.48%, and that added strain induces superconductivity. This is why it apparently works at room temperature — you no longer need high pressures or extreme cold to create the needed deformation.

Can’t really comment on how actually feasible or long-lasting this effect is, but it looks surprisingly promising. At least as a starting point for future experiments. Can’t wait for other labs’ reproduction attempts. If it turns out to be true, this is an extremely important and world-changing discovery.

Fingers crossed :)

The heat capacity results indicated that the new model is suitable for explaining the superconductivity of LK-99. The unique structure of LK-99 that allows the minute distorted structure to be maintained in the interfaces is the most important factor that LK-99 maintains and exhibits superconductivity at room temperatures and ambient pressure.

If true, that would have world-changing implications. I tried looking, but didn't see a paper to go with it or a second lab to confirm it. Still, very cool and hopefully will be confirmed.

If at all true this would be world-changing news.

Big, if true.

I'll believe it when science Youtubers start making videos on it.