Examine source code of HTML Tag Error Checker

{
  "version": "16.3.1",
  "background": {
    "scripts": [
      "js/contextMenus.js",
      "js/service-worker.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "32": "img/32.png",
      "48": "img/48.png",
      "64": "img/64.png",
      "200": "img/200.png",
      "500": "img/500.png"
    },
    "default_popup": "html/popup.html"
  },
  "content_scripts": [
    {
      "js": [
        "js/contents.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "icons": {
    "32": "img/32.png",
    "48": "img/48.png",
    "64": "img/64.png",
    "200": "img/200.png",
    "500": "img/500.png"
  },
  "options_ui": {
    "page": "html/setting.html",
    "open_in_tab": true
  },
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "contextMenus"
  ],
  "web_accessible_resources": [
    "js/*",
    "css/*",
    "img/*",
    "html/*",
    "_locales/*"
  ],
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{67d0c1ca-bbf4-4437-878e-2015ccdbcb5f}"
    }
  }
}