Examine source code of RoutineInk

{
  "manifest_version": 3,
  "name": "RoutineInk",
  "description": "Send the page you are reading to your Kindle now, or add it to a reading schedule.",
  "version": "0.1.8",
  "short_name": "RoutineInk",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "activeTab",
    "notifications",
    "storage",
    "contextMenus",
    "scripting",
    "alarms"
  ],
  "host_permissions": [
    "https://routineink.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@routineink.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "personallyIdentifyingInfo",
          "authenticationInfo",
          "browsingActivity",
          "websiteContent"
        ],
        "optional": []
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Send this page to your Kindle",
    "default_popup": "popup.html"
  }
}