Examine source code of Chatwork GitHub Extension

{
  "manifest_version" : 2 ,
  "name" : "Chatwork GitHub Extension",
  "version" : "0.1.0",
  "description" : "Browser extension to integrate Chatwork with GitHub.",
  "icons" : {
    "48" : "images/cwghe-icon-48.png",
    "96" : "images/cwghe-icon-96.png"
  },
  "permissions" : [
    "storage" ,
    "https://api.github.com/graphql" 
  ],
  "page_action" : {
    "show_matches": [
      "https://www.chatwork.com/*"
    ],
    "default_title" : "Chatwork GitHub Extension",
    "default_popup" : "pageAction.html",
    "default_icon" : "images/cwghe-icon-48.png",
    "browser_style": false
  },
  "options_ui" : {
    "page": "options.html" ,
    "open_in_tab": true
  },
  "content_scripts" : [
    {
      "matches" : [
        "https://www.chatwork.com/*" 
      ],
      "run_at" : "document_idle" ,
      "js" : [
        "contentScript.js" 
      ],
      "css" : [
        "style.css" 
      ]
    }
  ],
  "web_accessible_resources" : [
    "images/*.png",
    "template.html"
  ]
}