Examine source code of Word Replacer III

{
  "manifest_version": 3,
  "name": "Word Replacer III",
  "short_name": "WR III",
  "description": "Change your world one word at a time.",
  "version": "3.0.1",
  "icons": {
    "16": "images/icon_16.png",
    "32": "images/icon_32.png",
    "48": "images/icon_48.png",
    "128": "images/icon_128.png"
  },
  "background": {
    "scripts": [
      "event.js"
    ],
    "service_worker": "event.js"
  },
  "action": {
    "default_icon": {
      "16": "images/icon_16.png",
      "19": "images/icon_19.png",
      "32": "images/icon_32.png",
      "48": "images/icon_48.png"
    },
    "default_title": "Word Replacer III",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "all_frames": true,
      "js": [
        "jquery-2.1.4.min.js",
        "content_script.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "downloads"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "word-replacer-iii@extension",
      "strict_min_version": "109.0"
    }
  }
}