Examine source code of royalblue

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "royalblue",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(36, 35, 38)",
      "toolbar_text": "rgb(163, 159, 136)",
      "frame": "rgb(14, 41, 65)",
      "tab_background_text": "rgb(243, 222, 154)",
      "toolbar_field": "rgb(4, 1, 40)",
      "toolbar_field_text": "rgb(187, 185, 174)",
      "tab_line": "rgb(75, 28, 250)",
      "popup": "rgb(2, 34, 59)",
      "popup_text": "rgb(212, 200, 162)",
      "popup_highlight_text": "rgb(192, 184, 232)",
      "tab_loading": "rgb(75, 28, 250)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9b027dcc-4dc1-4413-8f19-a3072f374258}"
    }
  }
}