Examine source code of SubsNet SyncCookie

{
  "name": "CookieSyncer",
  "browser_specific_settings": {
    "gecko": {
      "id": "team@subsnet.app",
      "strict_min_version": "88.0"
    }
  },
  "version": "2.1.0",
  "description": "A firefox extension to synchronize cookies.",
  "icons": {
    "16": "icon/icon16.png",
    "48": "icon/icon48.png",
    "128": "icon/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icon/icon16.png",
      "48": "icon/icon48.png",
      "128": "icon/icon128.png"
    },
    "default_title": "CookieSyncer",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "cookies",
    "storage",
    "<all_urls>",
    "tabs"
  ],
  "manifest_version": 2
}