Why does the Codex app now require a phone number during login?

Welcome to the forum!

First I am not an OpenAI employee.

I looked for a direct answer to that in the OpenAI documentation, FAQ, issues, etc. and by having ChatGPT search and we could not find a direct answer.

ChatGPT did note

developers.openai.com

Authentication – Codex | OpenAI Developers

Sign-in methods for Codex

and in paticular this statement

Codex cloud interacts directly with your codebase, so it needs stronger security than many other ChatGPT features.

HTH