Examine source code of GriesmayerNoFlash

{
  "manifest_version": 2,
  "name": "GriesmayerNoFlash",
  "description": "Adds a \"Download\" button to videos which need Flash.",
  "version": "1.0",
  "author": "z3ntu",
  "homepage_url": "https://z3ntu.xyz",
  "content_scripts": [
    {
      "js": [
        "js/jquery-3.2.1.min.js",
        "js/script.js"
      ],
      "matches": [
        "*://griesmayer.com/*"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "*://griesmayer.com/*"
  ]
}