Examine source code of LocalTube Manager

{
  "manifest_version": 2,
  "name": "LocalTube Manager",
  "description": "A browser extension to use YouTube without a Google account",
  "version": "5.1.3",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "unlimitedStorage",
    "alarms",
    "notifications",
    "webRequest",
    "webRequestBlocking",
    "*://*.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "content-scripts/content.css"
  ],
  "browser_action": {},
  "browser_specific_settings": {
    "gecko": {
      "id": "{dbf09f58-dfd1-4825-963f-e76d5dc9ca2c}"
    }
  }
}