Examine source code of Customize TAB

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Customize TAB",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-005-f5f3cf677b1f132c75ddc7bd319dd1fc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(43, 206, 227)",
      "toolbar_text": "rgb(215, 226, 239)",
      "frame": "rgb(115, 214, 228)",
      "tab_background_text": "rgb(84, 84, 84)",
      "toolbar_field": "rgba(255, 255, 255, 0.53)",
      "toolbar_field_text": "rgb(255, 71, 203)",
      "tab_line": "rgb(255, 66, 205)",
      "popup": "rgb(231, 242, 244)",
      "popup_text": "rgb(84, 84, 84)",
      "icons_attention": "rgb(231, 242, 244)",
      "icons": "rgb(255, 66, 205)",
      "tab_loading": "rgb(255, 66, 205)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f3b3a94c-6e98-494c-a81e-d7f2ccfd89f5}"
    }
  }
}