Examine source code of Humalo Button

{
  "manifest_version": 2,
  "name": "Humalo Button",
  "version": "1.3.2.3resigned1",
  "description": "Save and organize content from the web with Humalo.",
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Click to view available Humalo actions."
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "web_accessible_resources": [
    "res/*"
  ],
  "permissions": [
    "activeTab",
    "tabs",
    "cookies",
    "https://humalo.com/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ec4054cf-6005-4006-8a71-3bfbb34d8a93}"
    }
  }
}