Examine source code of Random Frame Grabber

{
  "manifest_version": 2,
  "name": "Random Frame Grabber",
  "version": "1.0.0",
  "description": "Grab a random frame from videos or animated images (GIF/WebP).",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "permissions": [
    "contextMenus",
    "activeTab",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fb9a0bd3-1e4e-4c60-b3ba-9e8a8e761c2f}"
    }
  }
}