Ctrl+Z for YouTube

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Ctrl+Z for YouTube",
  "version": "1.0.3",
  "description": "Ever misclicked number keys while watching video and rewinded your movie? You can cancel it now!",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "contentscript.js"
      ],
      "all_frames": true,
      "run_at": "document_idle"
    }
  ],
  "permissions": [
    "*://*.youtube.com/*"
  ],
  "icons": {
    "128": "icon128.png"
  }
}