This is an example of the current spawn bonus chest loot table in Minecraft, in the (possibly) new loot table data format.

spawn_bonus_chest.json

[
  {
    "item": "minecraft:stick",
    "weight": 10,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 1,
        "max": 3
      }
    ]
  },
  {
    "item": "minecraft:planks",
    "weight": 10,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 1,
        "max": 3
      }
    ]
  },
  {
    "item": "minecraft:log",
    "weight": 10,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 1,
        "max": 3
      }
    ]
  },
  {
    "item": "minecraft:stone_axe",
    "weight": 3
  },
  {
    "item": "minecraft:wooden_axe",
    "weight": 5
  },
  {
    "item": "minecraft:stone_pickaxe",
    "weight": 3
  },
  {
    "item": "minecraft:wooden_pickaxe",
    "weight": 5
  },
  {
    "item": "minecraft:apple",
    "weight": 5,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 2,
        "max": 3
      }
    ]
  },
  {
    "item": "minecraft:bread",
    "weight": 3,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 2,
        "max": 3
      }
    ]
  },
  {
    "item": "minecraft:log2",
    "weight": 10,
    "functions": [
      {
        "function": "minecraft:set_count",
        "min": 1,
        "max": 3
      }
    ]
  }
]

I hacked around a little and have found this code, for anybody who wants to see.