Lighter updates

Changed

• Updating the client now downloads only what actually changed. Until now every fix meant pulling down the whole game resource pack again — from here on you get just the difference, usually a few hundred kilobytes instead of ten megabytes. This one update is still a full download: it is the baseline the differences are measured against.
• Files the game never opened are gone from the resource pack — among them 143 KB of the developer-facing change list. The notes you are reading here arrive separately, and that stays as it is.