Examine source code of e621 Easy View

{
  "manifest_version": 2,
  "name": "e621 Easy View",
  "version": "1.1",
  "description": "Adds view and download buttons to your e621 search results for easy viewing and downloading without opening a new tab or window.",
  "content_scripts": [
    {
      "matches": [
        "*://*.e621.net/*"
      ],
      "js": [
        "plugin.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4e1ba63d-8732-452a-a1ef-32486d29f0e9}"
    }
  }
}