Examine source code of Offline Read Aloud

{
  "manifest_version" : 3 ,
  "name" : "Offline Read Aloud",
  "version" : "1.1.8",
  "description" : "A fully offline Text-to-Speech reader for Firefox.",
  "permissions" : [
    "activeTab" ,
    "contextMenus" ,
    "storage" ,
    "scripting" 
  ],
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "action" : {
    "default_popup" : "popup.html",
    "default_title" : "Offline Read Aloud"
  },
  "content_scripts" : [
    {
      "matches" : [
        "http://*/*" ,
        "https://*/*" 
      ],
      "js" : [
        "lib/readability.js" ,
        "content.js" 
      ],
      "run_at" : "document_end" 
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "offline-read-aloud-paul-public@paul.local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}