Examine source code of GitHub URL Swapper

{
  "manifest_version": 2,
  "name": "GitHub URL Swapper",
  "version": "0.0.0.1",
  "description": "Jump between GH repo and GH Pages URLs",
  "homepage_url": "https://github.com/rahji/ghswapper_firefox",
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "16": "images/16icon.png",
      "32": "images/32icon.png",
      "48": "images/48icon.png",
      "128": "images/128icon.png"
    },
    "default_title": "GitHub URL Swapper"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4948af3-f973-4a34-8356-13198432cc8e}"
    }
  }
}