Examine source code of YTimestamps

{
  "manifest_version": 2,
  "name": "YTimestamps",
  "description": "Add timestamps to YouTube videos",
  "version": "0.0.1",
  "permissions": [
    "storage",
    "https://www.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "icons": {
    "16": "16.png",
    "32": "32.png",
    "64": "64.png",
    "128": "128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b6e5d157-f154-4df4-8a4e-5c274c71e643}"
    }
  }
}