Examine source code of Haunted Mound inspired

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Haunted Mound inspired",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(2, 20, 30)",
      "toolbar_text": "rgb(159, 0, 32)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 30, 30)",
      "toolbar_field": "rgb(19, 16, 16)",
      "toolbar_field_text": "rgb(255, 151, 0)",
      "tab_line": "rgb(176, 1, 3)",
      "popup": "rgb(33, 30, 30)",
      "popup_text": "rgb(255, 151, 0)",
      "icons": "rgb(219, 159, 0)",
      "tab_loading": "rgb(176, 1, 3)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b8d302f0-d035-41fa-9880-15948b2a18a0}"
    }
  }
}