Examine source code of Silver

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Silver",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(225, 234, 239, 0)",
      "toolbar_text": "rgb(225, 200, 247)",
      "frame": "rgb(136, 141, 202)",
      "tab_background_text": "rgb(254, 205, 216)",
      "toolbar_field": "rgba(255, 255, 255, 0)",
      "toolbar_field_text": "rgb(173, 168, 246)",
      "tab_line": "rgb(179, 32, 4)",
      "popup": "rgba(90, 88, 92, 0.67)",
      "popup_text": "rgb(240, 240, 248)",
      "button_background_active": "rgba(255, 255, 255, 0)",
      "toolbar_field_border": "rgb(40, 6, 240)",
      "toolbar_field_focus": "rgba(144, 145, 146, 0)",
      "toolbar_field_highlight_text": "rgb(20, 10, 0)",
      "toolbar_field_highlight": "rgba(252, 243, 233, 0)",
      "toolbar_field_text_focus": "rgba(233, 232, 230, 0)",
      "tab_loading": "rgb(179, 32, 4)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1428a138-4492-4d3b-973f-287cf9737b77}"
    }
  }
}