Change record status: 
Project: 
Introduced in branch: 
8.x
Description: 

The theme_system_powered_by() theme function has been removed from core. theme_system_powered_by() returned a simple string of markup and was only used to render the contents of the "Powered by Drupal" block. The "Powered by Drupal" block plugin now includes this markup directly rather than calling out to a theme function.

To build a custom "Powered by" block you can create a custom block with your own markup or use a string override to customize the existing "Powered by Drupal" block content.

Impacts: 
Themers