Examine source code of Mock Express

{
  "name": "Mock Express: API Mocker & Interceptor",
  "description": "A Browser extension that intercepts and modifies HTTP requests/responses.",
  "version": "2.0.5",
  "manifest_version": 2,
  "incognito": "spanning",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Mock Express!",
    "default_icon": "icon-48.png"
  },
  "permissions": [
    "storage",
    "unlimitedStorage",
    "contextMenus",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "icon.png",
    "pageInterceptorEntryPoint.js",
    "app.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b6f13861-28bc-4c05-a810-690e4e916c7d}"
    }
  }
}