What was added/changed was these two items:
- On macOS, closing the last vault and re-activating Obsidian will now re-open the last vault instead of opening the vault switcher.
- On macOS, quitting and restarting the app will properly restore the opened vaults.
So, no setting or customization on how Obsidian starts up.
For the record, I’d love a preference for showing the Vault Chooser on startup rather than “Last Obsidian Vault that was closed” as the current way makes startup depend on how you shut down your Obsidian Vaults before.