Examine source code of Spotify Close Protector

{
  "description": "Prevents accidental tab or window closing when Spotify is open.",
  "manifest_version": 2,
  "name": "Spotify Close Protector",
  "version": "1",
  "icons": {
    "48": "i.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://open.spotify.com/*"
      ],
      "js": [
        "p.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b55e7933-7133-4b2b-9373-ffe9743a1357}"
    }
  }
}