Examine source code of Swirling Blackhole

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Swirling Blackhole",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0.81)",
      "toolbar_text": "rgb(255, 166, 0)",
      "frame": "rgb(157, 183, 190)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 200, 0)",
      "toolbar_field_text": "rgb(90, 93, 154)",
      "tab_line": "rgb(255, 171, 41)",
      "popup": "rgb(5, 10, 57)",
      "popup_text": "rgb(0, 247, 255)",
      "tab_loading": "rgb(255, 171, 41)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8800d4d6-2075-439d-bdcd-62f143417900}"
    }
  }
}