Minecraft wiki entry for Development_versions, associated text: Added Item Lock components to allow for items to be locked in the inventory, locked in a slot, or kept upon death.
Added a new loop_delayfield to skeletal animation files that controls how to wait between each iteration of a looping animation.
Added camerashake command to enable a camera shaking effect.
Villagers/zombie villagers will once again correctly spawn as a baby when using the summon command to summon them with the event minecraft:entity_born.
Older command versions using /execute will now use the proper position for command selectors when calculating the radius.