Change record status: 
Project: 
Introduced in branch: 
9.3.x
Introduced in version: 
9.3.0
Description: 

The user ID's are now generated by an auto-increment value from the database, like it is for almost all other entities. User generation no longer uses the sequences API - ie. \Drupal\Core\Database\Connection::nextId().

Impacts: 
Site builders, administrators, editors
Module developers
Site templates, recipes and distribution developers