Examine source code of Comfortable Sakai

{
  "name": "Comfortable Sakai",
  "description": "__MSG_EXTENSION_DESCRIPTION__",
  "version": "2.0.1",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "img/icon16.png",
    "48": "img/icon48.png",
    "128": "img/icon128.png"
  },
  "browser_action": {
    "default_title": "Comfortable Sakai",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "js": [
        "content_script.js"
      ],
      "css": [
        "css/comfortable-sakai.css"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "storage"
  ],
  "web_accessible_resources": [
    "css/comfortable-sakai.css",
    "img/logo.png",
    "img/noAssignment.png",
    "img/miniSakaiBtn.png",
    "img/closeBtn.svg"
  ],
  "applications": {
    "gecko": {
      "id": "comfortable.sakai@kyoto-u"
    }
  }
}