Examine source code of GOTO2021

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "GOTO2021",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat-x"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0)",
      "toolbar_text": "rgb(0, 7, 8)",
      "frame": "rgb(5, 5, 5)",
      "tab_background_text": "rgb(3, 0, 0)",
      "toolbar_field": "rgba(0, 0, 0, 0.25)",
      "toolbar_field_text": "rgb(6, 5, 7)",
      "tab_line": "rgba(0, 0, 0, 0.45)",
      "popup": "rgba(5, 0, 14, 0.29)",
      "popup_text": "rgb(201, 165, 84)",
      "tab_loading": "rgba(0, 0, 0, 0.45)"
    }
  }
}