Examine source code of Companion Reader

{
  "manifest_version": 2,
  "name": "Companion Reader",
  "version": "7.3",
  "description": "Highlights webpage text word-by-word.",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_title": "Companion Reader",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png",
    "96": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{648bdc74-94c6-4196-8789-d5947268867c}"
    }
  }
}