Examine source code of Full Width Git Hub 2

{
  "manifest_version": 2,
  "name": "Full Width Git Hub",
  "description": "Adds full page width to git hub",
  "version": "2.3resigned1",
  "browser_action": {
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs",
    "https://github.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{80e5aa69-3992-487c-becb-78cee58a4e6a}"
    }
  }
}