Which tag settings option is NOT used for tagging users in a web application?

The option that is not used for tagging users in a web application is XML attributes. Tagging users typically relies on more dynamic and interactive methods that directly engage with the client-side elements of a web application or its server-side processes.

CSS selectors are widely used for identifying elements in the DOM (Document Object Model) of a webpage, allowing developers to assign tags based on the structure and styling of the webpage. JavaScript variables can hold user session data, preferences, or other dynamic information that can be sent for tagging during user interactions. Server-side request attributes enable the application to associate user-specific data with requests processed on the server, facilitating tagging based on input received from users.

In contrast, XML attributes do not directly function in the same immediate context for tagging users within web applications. While they can provide metadata within XML documents, they do not interact with the website's user interface or behavior in a way that supports the tagging functionality required in web applications.