Examine source code of Not-so-serious

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Not-so-serious",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(62, 39, 35)",
      "toolbar_text": "rgb(248, 112, 140)",
      "frame": "rgb(239, 108, 0)",
      "tab_background_text": "rgb(255, 236, 179)",
      "toolbar_field": "rgb(0, 96, 100)",
      "toolbar_field_text": "rgb(255, 138, 101)",
      "tab_line": "rgb(62, 255, 197)",
      "popup": "rgb(0, 96, 100)",
      "popup_text": "rgb(255, 138, 101)",
      "button_background_hover": "rgba(244, 81, 30, 0.67)",
      "icons": "rgb(62, 255, 197)",
      "ntp_text": "rgb(229, 255, 62)",
      "tab_loading": "rgb(62, 255, 197)"
    }
  }
}