Examine source code of Hide Upgrade Button for Gmail, Drive & Docs

{
  "manifest_version": 3,
  "name": "__MSG_name__",
  "description": "__MSG_description__",
  "default_locale": "en",
  "icons": {
    "16": "assets/icons/icon-16.png",
    "32": "assets/icons/icon-32.png",
    "48": "assets/icons/icon-48.png",
    "128": "assets/icons/icon-128.png"
  },
  "action": {
    "default_title": "__MSG_name__",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "assets/icons/icon-16.png",
      "32": "assets/icons/icon-32.png",
      "48": "assets/icons/icon-48.png",
      "128": "assets/icons/icon-128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*",
        "https://drive.google.com/*",
        "https://docs.google.com/*"
      ],
      "js": [
        "content-script.js"
      ],
      "css": [
        "prehide.css"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "https://mail.google.com/*",
    "https://drive.google.com/*",
    "https://docs.google.com/*"
  ],
  "optional_host_permissions": [
    "https://calendar.google.com/*"
  ],
  "version": "0.2.0",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "hide-gmail-upgrade-button@maximtop.dev",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}