Examine source code of HirePeople

{
  "manifest_version": 3,
  "name": "HirePeople",
  "description": "Send highly personalized LinkedIn messages. Instantly.",
  "version": "1.2.8",
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "64": "icon-64.png",
    "128": "icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "hello@hirepeople.com"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.linkedin.com/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "svg/*",
        "font/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}