Examine source code of Custom Header Tailor

{
  "manifest_version": 3,
  "name": "__MSG_extName__",
  "version": "1.0.1",
  "description": "__MSG_extDescription__",
  "default_locale": "en",
  "author": "Antonio Rusconi",
  "homepage_url": "https://gitlab.com/mrdjtoto/mozilla-custom-headers",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "custom-headers@mrdjtoto.gitlab.io",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "declarativeNetRequest",
    "declarativeNetRequestWithHostAccess",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "__MSG_actionTitle__",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    }
  }
}