I tweak LO often, but I think the recent changes are particularly significant, even though they're not huge feature upgrades. These are the tweaks for user onboarding and Memorizing parts.
For user onboarding, I even made the Playground, but I realized that users don't like it than I thought.
So instead of that, I put the example data in the Organizing part itself for the first-time users.
So, the user can immediately see how the data is shown in the Memorizing part (this was something I didn't think users would want).
And one day, I feel annoyed about the Product Tours I wrote, so I simplified them all. It seems to be much better now.
As for the Memorizing part,
it was quite ugly. (Unfortunately, there is no image of that time. I should have left a screenshot. But it was really ugly.)
Now it looks much, much prettier. The point I particularly like is that now cards clearly look like certain parts of the tree.
I hope I did these before being featured on Hacker News. But I couldn't...