Examine source code of Rickrollify

{
  "manifest_version": 2,
  "name": "Rickrollify",
  "version": "2.0.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "rickrollify@delizioso_at_codeberg.org"
    }
  },
  "description": "An extension that grants you a 1% chance of injecting Rick Astley on every new page load.",
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "exclude_matches": [
        "https://www.youtube.com/watch?v=dQw4w9WgXcQ"
      ],
      "js": [
        "jquery-3.5.1.min.js",
        "background.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "*://*/*"
  ],
  "icons": {
    "32": "icons/32x32.png",
    "128": "icons/128x128.png"
  },
  "homepage_url": "https://codeberg.org/duck/Rickrollify"
}