Examine source code of Video SS

{
  "manifest_version": 2,
  "name": "Video SS",
  "description": "タブのスクショを撮ってvideoタグのところだけ切り抜くやつ",
  "version": "0.1.1",
  "browser_action": {
    "default_title": "Video SS",
    "default_popup": "popup.html"
  },
  "permissions": [
    "<all_urls>"
  ]
}