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"
  ]
}