After T359962 and T341827, the CheckUser ipusers API has a empty name for private events performed by IP addresses when temporary accounts are enabled. This is because the code is missing to convert the null value of actor_name to the IP address.

Example:

Steps to replicate the issue

1. Enable temporary accounts
2. Set $wgCheckUserLogLogins = true; and $wgCheckUserEventTablesMigrationStage = SCHEMA_COMPAT_NEW; in LocalSettings.php
3. While not logged in to a temporary account (exit the session if this is the case), make a failed login attempt using Special:UserLogin
4. Run ipusers CheckUser API request

What happens?:
An entry exists with name as an empty string.

What should have happened instead?:
The name should the IP address.