Examine source code of Double Koi Hack

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "double koi",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png",
        "images/1.png",
        "images/2.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top",
        "right bottom",
        "left center"
      ],
      "additional_backgrounds_tiling": [
        "repeat",
        "repeat",
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(79, 109, 137, 0.52)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(87, 160, 167)",
      "tab_background_text": "rgb(255, 90, 187)",
      "toolbar_field": "rgba(220, 29, 106, 0.15)",
      "toolbar_field_text": "rgb(198, 195, 220)",
      "tab_line": "rgba(16, 223, 223, 0.53)",
      "popup": "rgba(222, 222, 222, 0.88)",
      "popup_text": "rgb(6, 146, 130)",
      "button_background_active": "rgba(225, 239, 114, 0.4)",
      "button_background_hover": "rgba(255, 249, 120, 0.47)",
      "frame_inactive": "rgba(235, 173, 173, 0.83)",
      "icons_attention": "rgba(117, 243, 193, 0.54)",
      "icons": "rgb(255, 255, 255)",
      "ntp_background": "rgba(180, 240, 192, 0.73)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgba(143, 162, 207, 0.38)",
      "popup_highlight_text": "rgb(255, 183, 183)",
      "popup_highlight": "rgb(122, 228, 232)",
      "sidebar_border": "rgb(90, 90, 115)",
      "sidebar_highlight_text": "rgb(216, 240, 214)",
      "sidebar_highlight": "rgba(236, 244, 89, 0.27)",
      "sidebar_text": "rgb(225, 221, 241)",
      "sidebar": "rgb(77, 50, 61)",
      "tab_background_separator": "rgba(22, 22, 22, 0.08)",
      "tab_loading": "rgba(187, 212, 255, 0.98)",
      "tab_selected": "rgba(137, 190, 153, 0.18)",
      "tab_text": "rgba(255, 255, 255, 0.98)",
      "toolbar_bottom_separator": "rgba(160, 160, 160, 0.73)",
      "toolbar_field_border_focus": "rgba(190, 199, 226, 0.49)",
      "toolbar_field_border": "rgba(120, 104, 145, 0.43)",
      "toolbar_field_focus": "rgba(183, 197, 202, 0.19)",
      "toolbar_field_highlight_text": "rgba(184, 48, 101, 0.18)",
      "toolbar_field_highlight": "rgba(214, 33, 103, 0.18)",
      "toolbar_field_separator": "rgba(236, 143, 179, 0.18)",
      "toolbar_field_text_focus": "rgba(236, 142, 187, 0.31)",
      "toolbar_top_separator": "rgba(57, 48, 134, 0.44)",
      "toolbar_vertical_separator": "rgba(73, 51, 77, 0.09)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{62122a8c-8809-4a3e-a521-9b3b48d929dd}"
    }
  }
}