Examine source code of Eye don't know ...

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "eye-don-t-know2 ",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(8, 11, 33)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(255, 255, 255, 0.26)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgba(0, 0, 0, 0.8)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgba(0, 204, 255, 0.57)",
      "button_background_hover": "rgba(255, 255, 255, 0.34)",
      "icons_attention": "rgba(255, 255, 255, 0.71)",
      "ntp_text": "rgb(255, 255, 255)",
      "sidebar_highlight_text": "rgba(255, 255, 255, 0)",
      "sidebar_highlight": "rgba(255, 255, 255, 0)",
      "tab_background_separator": "rgb(255, 255, 255)",
      "tab_loading": "rgb(0, 142, 255)",
      "tab_selected": "rgba(0, 204, 255, 0.26)",
      "tab_text": "rgb(255, 210, 0)",
      "toolbar_bottom_separator": "rgba(0, 0, 0, 0)",
      "toolbar_field_border_focus": "rgb(0, 0, 0)",
      "toolbar_field_border": "rgba(0, 204, 255, 0.57)",
      "toolbar_field_focus": "rgba(255, 255, 255, 0)",
      "toolbar_field_highlight": "rgb(255, 255, 255)",
      "toolbar_field_separator": "rgba(255, 255, 255, 0)",
      "toolbar_top_separator": "rgba(255, 255, 255, 0)",
      "toolbar_vertical_separator": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{be913752-f564-418e-bad5-536098a0c603}"
    }
  }
}