Examine source code of Embed to Link

{
  "manifest_version": 2,
  "name": "Embed to Link",
  "version": "1.0",
  "description": "Converts video site embeds into clickable links",
  "browser_specific_settings": {
    "gecko": {
      "id": "embedtolink@example.com"
    }
  },
  "icons": {
    "48": "icons/E2L.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "exclude_matches": [
        "http://www.youtube.com/*",
        "https://www.youtube.com/*",
        "https://vimeo.com/*"
      ],
      "run_at": "document_start",
      "all_frames": true,
      "js": [
        "embedtolink.js"
      ]
    }
  ]
}