Examine source code of Endless Sky Background

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Endless Sky Background",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(32, 32, 32, 0)",
      "toolbar_text": "rgb(231, 231, 231)",
      "frame": "rgb(32, 32, 32)",
      "tab_background_text": "rgb(104, 104, 104)",
      "toolbar_field": "rgba(104, 104, 104, 0.5)",
      "toolbar_field_text": "rgb(231, 231, 231)",
      "tab_line": "rgb(167, 167, 66)",
      "popup": "rgb(40, 40, 40)",
      "popup_text": "rgb(167, 167, 167)",
      "button_background_active": "rgb(231, 231, 231)",
      "icons_attention": "rgb(231, 231, 231)",
      "icons": "rgb(104, 104, 104)",
      "ntp_background": "rgb(32, 32, 32)",
      "popup_border": "rgb(125, 125, 125)",
      "popup_highlight": "rgb(231, 231, 231)",
      "sidebar_border": "rgb(125, 125, 125)",
      "sidebar_highlight_text": "rgb(231, 231, 231)",
      "tab_background_separator": "rgb(125, 125, 125)",
      "tab_selected": "rgb(40, 40, 40)",
      "tab_text": "rgb(167, 167, 66)",
      "toolbar_field_separator": "rgba(104, 104, 104, 0)",
      "toolbar_top_separator": "rgba(104, 104, 104, 0)",
      "tab_loading": "rgb(167, 167, 66)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2f097c12-8319-4624-a03d-ed71bf6a0ab6}"
    }
  }
}