Packwright

First release (Alpha).

• Leather Field Pack (27 slots) and Reinforced Artisan Pack (54 slots), each with a reserve slot for an elytra or chestplate. Upgrading keeps everything inside.
• Open a pack with right-click, the B key, or right-click on it in your inventory.
• Quick-stack (K or the copper button) sends items to nearby chests, barrels and shulker boxes that already hold them. Hotbar, armour, off-hand and locked slots are never touched.
• Alt + click locks a slot.
• Sort buttons for packs, your inventory and chests.
• Auto-refill: when you place your last block or break a tool, the slot refills from your inventory or pack.
• G swaps your elytra and chestplate.
• Server config: turn quick-stack, auto-refill or the swap on or off, and set the quick-stack radius.

Alpha: please report bugs, especially around multiplayer and other inventory mods.