Examine source code of Combine URL

{
  "manifest_version": 2,
  "name": "Combine URL Extensions",
  "version": "1.0",
  "description": "Combines url parts",
  "icons": {
    "48": "icon48.png"
  },
  "permissions": [
    "storage",
    "http://*/*",
    "https://*/*",
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Url Combine",
    "default_popup": "index.html"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+F",
        "mac": "MacCtrl+Shift+F"
      },
      "description": "Combines url parts"
    }
  }
}