Examine source code of Minecraft: Grass Block

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Minecraft: Grass Block",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(60, 150, 57, 0.43)",
      "toolbar_field": "rgba(58, 105, 56, 0.37)",
      "toolbar_field_text": "rgb(109, 222, 105)",
      "tab_line": "rgb(75, 211, 96)",
      "popup": "rgb(58, 104, 51)",
      "popup_text": "rgb(217, 217, 217)",
      "tab_loading": "rgb(75, 211, 96)",
      "bookmark_text": "rgb(255, 255, 255)",
      "frame": "rgb(73, 161, 60)",
      "tab_background_text": "rgb(0, 0, 0)"
    }
  }
}