Examine source code of Alerta Notifier

{
  "name": "Alerta Notifier",
  "description": "A simple web extension that notifies when new alerts are in Alerta",
  "manifest_version": 2,
  "version": "2.0.0",
  "icons": {
    "16": "alert.png",
    "48": "alert.png",
    "128": "alert.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "alert.png",
      "48": "alert.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "optional_permissions": [
    "<all_urls>"
  ],
  "permissions": [
    "storage",
    "alarms",
    "notifications"
  ],
  "web_accessible_resources": [
    "alert.png",
    "bootstrap.min.css",
    "bip.mp3"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1c1072ed-06ff-4556-ac51-d8f02020ed86}"
    }
  }
}