Examine source code of Gmail shortcut

{
  "manifest_version": 2,
  "name": "Gmail shortcut",
  "version": "1.0",
  "description": "Adds a direct shortcut to Gmail to be opened in an active tab.",
  "icons": {
    "48": "logo.png"
  },
  "browser_action": {
    "default_icon": "logo.png",
    "default_title": "Gmail"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}