Examine source code of Word Replace

{
  "manifest_version": 2,
  "name": "Word Replacer",
  "version": "1.0",
  "description": "Replace specified words on webpages and in form fields",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "permissions": [
    "storage",
    "<all_urls>"
  ],
  "browser_action": {
    "default_icon": "icon.svg",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c44c79c7-2129-4c70-960e-7fcc7ecf975f}"
    }
  }
}