Examine source code of VidPeaks

{
  "manifest_version": 2,
  "name": "VidPeaks",
  "short_name": "VidPeaks",
  "version": "1.2.1",
  "description": "Highlights the most watched parts in YouTube-videos",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "vidpeaks@cr4xy.dev",
      "strict_min_version": "58.0"
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "24": "icon24.png",
      "32": "icon32.png"
    },
    "default_title": "VidPeaks",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "author": "Cr4xy",
  "homepage_url": "https://cr4xy.de/vidpeaks",
  "content_scripts": [
    {
      "matches": [
        "https://youtube.com/*",
        "https://www.youtube.com/*"
      ],
      "js": [
        "inject.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "tabs",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "https://youtube.com/*",
    "https://www.youtube.com/*"
  ],
  "web_accessible_resources": [
    "contentScript.js"
  ]
}