Examine source code of minecraft hallowin

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "minecraft hallowin",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat-y"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0.15)",
      "toolbar_text": "rgb(249, 248, 253)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(249, 248, 253)",
      "toolbar_field": "rgba(40, 3, 251, 0.5)",
      "toolbar_field_text": "rgb(249, 248, 253)",
      "tab_line": "rgb(14, 123, 15)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(246, 152, 5)",
      "ntp_background": "rgb(29, 219, 155)",
      "tab_loading": "rgb(14, 123, 15)"
    }
  }
}