Examine source code of Engager

{
  "description": " Increase your level of work engagement and productivity.",
  "icons": {
    "16": "icons/engager-icon-16.png",
    "128": "icons/engager-icon-128.png"
  },
  "browser_action": {
    "default_icon": "icons/engager-icon-16.png",
    "default_title": "Engager"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "support@engager.pro",
      "strict_min_version": "45.0"
    }
  },
  "manifest_version": 2,
  "name": "Engager",
  "permissions": [
    "tabs"
  ],
  "version": "1.1resigned1"
}