YouTube in HD (720p, 1080p, 1440p, 2160p)

manifest.json

{
  "name": "Auto High Quality for YouTube™",
  "description": "Automatically change YouTube video quality to HD resolution or the highest available one",
  "version": "0.3.3",
  "manifest_version": 2,
  "permissions": [
    "storage"
  ],
  "background": {
    "persistent": false,
    "scripts": [
      "common.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "data/code.js",
        "data/inject.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "homepage_url": "https://webextension.org/listing/youtube-hd.html",
  "options_ui": {
    "page": "data/options/index.html"
  },
  "icons": {
    "16": "data/icons/16.png",
    "19": "data/icons/19.png",
    "32": "data/icons/32.png",
    "38": "data/icons/38.png",
    "48": "data/icons/48.png",
    "128": "data/icons/128.png",
    "256": "data/icons/256.png",
    "512": "data/icons/512.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "jid0-RjdrEcWS3Ggt4xydeqVS8WQk1Lu@jetpack"
    }
  }
}