Examine source code of SidebarDie

{
  "manifest_version": 2,
  "name": "SidebarDie",
  "version": "1.0",
  "description": "Just hides the sidebar on the reddit site. That's it.",
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/*"
      ],
      "js": [
        "sidebarbegone.js"
      ]
    }
  ]
}