Obsidian Sync now has a headless client, allowing for automated backups, publishing, and syncing of vaults. The headless client provides a more integrated experience, with features like version history and fine-grained control. This development is expected to be useful for users who want to automate tasks and sync their vaults without having to open the full Obsidian app. The headless client is part of Obsidian's paid sync service, which provides additional features and support.