Examine source code of APK Engineer

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "APK Engineer",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(30, 65, 91)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(17, 89, 155)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(47, 104, 155)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(10, 195, 230)",
      "popup": "rgb(27, 124, 201)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(10, 195, 230)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5633e999-481f-4949-a2fa-c4a64d2a950a}"
    }
  }
}