manifest.json

{

  "description": "Adds a solid red border to all webpages matching mozilla.org. See https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples#borderify",
  "manifest_version": 3,
  "name": "Borderify",
  "version": "1.0",
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/borderify",
  "icons": {
    "48": "icons/border-48.png"
  },

  "browser_specific_settings": {
    "gecko": {
      "id": "borderify@mozilla.org",
      "data_collection_permissions": {
        "required": ["none"]
      }
    }
  },

  "content_scripts": [
    {
      "matches": ["*://*.mozilla.org/*"],
      "js": ["borderify.js"]
    }
  ]

}