Examine source code of Word Reminder

{
  "manifest_version": 3,
  "version": "1.1.3",
  "description": "Allows users to store and remind themselves of words in their dictionary to improve vocabulary and increase word retention.",
  "name": "Word Reminder",
  "action": {
    "default_popup": "index.html?popup=true"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@oejlbeackbidindbmobdbcfhjieljhji"
    }
  },
  "background": {
    "scripts": [
      "service-worker.js"
    ],
    "type": "module"
  },
  "permissions": [
    "contextMenus",
    "notifications",
    "storage"
  ],
  "host_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "icons": {
    "16": "images/word-reminder-16x16.png"
  }
}