Examine source code of Web Video Keyboard Nav

{
  "manifest_version": 2,
  "name": "Web Video Keyboard Nav",
  "version": "3.0.1",
  "description": "Navigating video sites with keyboard arrow keys.",
  "icons": {
    "48": "icon-48.png",
    "96": "icon-96.png",
    "128": "icon-128.png",
    "512": "icon-512.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "web-video-keyboard-nav@cute.computer",
      "strict_min_version": "140.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.netflix.com/*",
        "https://www.zdf.de/*",
        "https://www.ardmediathek.de/*"
      ],
      "run_at": "document_end",
      "js": [
        "index.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}