Examine source code of goto 2021

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "goto 2021",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(225, 234, 239, 0)",
      "toolbar_text": "rgba(225, 234, 239, 0.59)",
      "frame": "rgb(0, 2, 3)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(0, 2, 3, 0.3)",
      "toolbar_field_text": "rgba(225, 234, 239, 0.59)",
      "tab_line": "rgba(248, 112, 140, 0.5)",
      "popup": "rgba(0, 2, 3, 0.22)",
      "popup_text": "rgb(156, 107, 12)",
      "tab_loading": "rgba(248, 112, 140, 0.5)"
    }
  }
}