Examine source code of Date and clock

{
  "manifest_version": 2,
  "name": "Date and clock",
  "version": "4.6",
  "permissions": [
    "alarms",
    "theme",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/dac-32.png",
    "default_title": "Date and clock",
    "browser_style": false
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/dac-48.png"
  },
  "applications": {
    "gecko": {
      "id": "dobrojutro@dac.com",
      "strict_min_version": "55.0a1"
    }
  }
}