Examine source code of Glexa Fullscreen Button

{
  "name": "Glexa Fullscreen Button",
  "version": "0.0.2.1",
  "manifest_version": 2,
  "description": "VERSION2社のLMS「Glexa」のSCORM教材画面に、教材をフルスクリーン化するボタンを追加します。",
  "content_scripts": [
    {
      "matches": [
        "https://*.glexa.net/content/*/scorm/",
        "https://*.glexa.net/content/*/scorm/*/",
        "https://*.glexa.net/plugin/scorm/*/*/"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": []
}