Examine source code of Image Navigation Buttons

{
  "author": "Steffen Bahrmann <steffen.bahrmann@404-labor.de>",
  "manifest_version": 3,
  "name": "Image Navigation Buttons",
  "version": "1.0",
  "description": "Navigate between sequential images in the browser.",
  "permissions": [
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "s.bahrmann@gmail.com"
    }
  }
}