Don't know whether this is a bug (so feel free to ruthlessly hide me), but the new sidebar thing: Can I make it go away?

This is on iPad, yes? @samuel.bsky.team can correct me if I'm wrong, but I believe it should go away if you turn your iPad so that it's vertical instead of horizontal (or resize the window so that it's less wide)

No — it's a Macbook. The sidebar does go away on the laptop if I resize, but I'm for some reason deeply disconcerted by the new smaller viewing pane. There's a good chance that, as of, say, later today, I won't notice the sidebar anymore, so I've decided panic is probably unnecessary.

Oh, how interesting! I use Bluesky on my MacBook, and I haven't seen any change: that column has always been there. I wonder why it's different for you! Is yours a very small one, e.g., 12-inch? Anyhow, apologies for prolonging this, and as you say, I'm sure you'll stop noticing it in a few hours