Examine source code of Outlook Web Inbox Count

{
  "manifest_version": 3,
  "name": "Outlook Web Inbox Count",
  "version": "1.3",
  "description": "Adds the total number of items next to the Inbox label in Outlook Web",
  "author": "Giorgio Gilestro",
  "homepage_url": "https://lab.gilest.ro",
  "browser_specific_settings": {
    "gecko": {
      "id": "outlook-inbox-count@gilest.ro"
    }
  },
  "permissions": [],
  "host_permissions": [
    "https://outlook.office.com/*",
    "https://outlook.office365.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://outlook.office.com/*",
        "https://outlook.office365.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "icon16.png",
    "64": "icon64.png",
    "128": "icon128.png"
  }
}