Examine source code of GatherTube

{
  "manifest_version": 2,
  "name": "GatherTube",
  "version": "1.1.1",
  "description": "Gather all open YouTube video tabs into a single queue for seamless watching",
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{e280f7f2-4fb5-455d-a396-9f09533d9060}"
    }
  },
  "permissions": [
    "tabs",
    "storage",
    "*://*.youtube.com/*",
    "*://*.youtu.be/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "GatherTube",
    "default_icon": {
      "16": "icons/icon-16.png",
      "19": "icons/icon-19.png",
      "32": "icons/icon-32.png",
      "38": "icons/icon-38.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "128": "icons/icon-128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "icons/icon-16.png",
    "19": "icons/icon-19.png",
    "32": "icons/icon-32.png",
    "38": "icons/icon-38.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png",
    "256": "icons/icon-256.png"
  },
  "options_page": "options.html",
  "web_accessible_resources": [
    "embed_page.html"
  ]
}