Examine source code of Super CSS Inject

{
  "name": "Super CSS Inject",
  "version": "1.2.0",
  "description": "Keep multiple stylesheets ready to inject and change on the fly!",
  "manifest_version": 2,
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "48": "icons/48x48.png",
    "64": "icons/64x64.png",
    "128": "icons/128x128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "SuperCSSInject.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_action": {
    "default_title": "Enable Super CSS Inject",
    "default_icon": "icons/48x48.png",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  }
}