Examine source code of Containers Sync

{
  "description": "Sync containers across multiple devices",
  "manifest_version": 2,
  "name": "Containers Sync",
  "version": "1.1.4",
  "permissions": [
    "alarms",
    "contextualIdentities",
    "storage"
  ],
  "icons": {
    "48": "./resources/icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "sync@containers",
      "strict_min_version": "55.0"
    }
  },
  "browser_action": {
    "default_popup": "popup.html",
    "browser_style": true,
    "default_icon": "./resources/icon.png"
  },
  "sidebar_action": {
    "default_panel": "sidebar.html",
    "default_icon": "./resources/icon.png"
  }
}