What does an analyst need to describe for a 404 to be handled correctly?

The analyst needs to describe the following points for correct handling of the 404 error:

• Conditions of occurrence: when exactly the server should return a 404 (for example, when the requested resource is not found).
• System behavior: what should happen when a 404 is received — display a message page, redirect, log.
• Error page text and design: what text, style, and interface elements should be on the 404 page.
• Impact on user experience: how the user should understand the error and what actions are offered (for example, a link to the homepage).
• Technical details: response format (HTML, JSON), HTTP headers, caching.

A clear description of these aspects will allow developers and testers to implement and verify correct handling of 404.