Examine source code of Greygender flag

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Greygender flag",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(41, 41, 41, 0.82)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(188, 188, 188)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(6, 35, 131)",
      "popup": "rgb(83, 83, 83)",
      "popup_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(6, 35, 131)",
      "tab_loading": "rgb(6, 35, 131)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9ca2e70f-7fcf-4c25-b1b2-cda1457b87c7}"
    }
  }
}