Examine source code of Simple Blue for Firefox

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Simple Blue",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(249, 249, 251)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(35, 48, 90)",
      "tab_background_text": "rgb(249, 249, 251)",
      "toolbar_field": "rgb(240, 240, 244)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(35, 48, 90)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 0, 0)",
      "ntp_background": "rgb(242, 247, 251)",
      "popup_border": "rgb(240, 240, 244)",
      "tab_loading": "rgb(35, 48, 90)",
      "toolbar_bottom_separator": "rgb(204, 204, 204)",
      "toolbar_field_border_focus": "rgb(127, 176, 239)",
      "toolbar_field_border": "rgb(208, 208, 215)",
      "toolbar_top_separator": "rgb(35, 48, 90)"
    }
  }
}