Examine source code of Zulu Sensim

{
  "manifest_version": 2,
  "name": "Zulu Sensim",
  "version": "2.9.0",
  "description": "Learn Zulu while you browse. 3 new words replace themselves every day.",
  "permissions": [
    "storage",
    "activeTab",
    "notifications",
    "alarms",
    "*://*/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "config.js",
        "sync.js",
        "vocab.js",
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Zulu Sensim"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "sensim-zulu@sensim.app",
      "strict_min_version": "91.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "121.0"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}