Examine source code of witch poison

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "poison",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(7, 50, 84, 0)",
      "toolbar_text": "rgb(130, 73, 174)",
      "frame": "rgb(130, 162, 97)",
      "tab_background_text": "rgb(96, 136, 56)",
      "toolbar_field": "rgba(67, 98, 36, 0.35)",
      "toolbar_field_text": "rgb(130, 73, 174)",
      "tab_line": "rgba(130, 162, 97, 0.86)",
      "popup": "rgb(96, 136, 56)",
      "popup_text": "rgb(0, 0, 0)",
      "ntp_background": "rgb(58, 37, 74)",
      "ntp_text": "rgb(130, 162, 97)",
      "tab_loading": "rgba(130, 162, 97, 0.86)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1975949a-bef4-4e91-b61c-d54c3ef3c4cb}"
    }
  }
}