Examine source code of full screenpro

{
  "name": "full screenpro",
  "short_name": "Google Keep Full Screen",
  "description": "Makes note editing take up the full browser window",
  "homepage_url": "https://github.com/chrisputnam9/chrome-google-keep-full-screen",
  "version": "1.2.1",
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "permissions": [
    "*://keep.google.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://keep.google.com/*"
      ],
      "css": [
        "src/styles.css"
      ],
      "js": [
        "src/script.js"
      ],
      "run_at": "document_end"
    }
  ],
  "manifest_version": 2
}