By catch on
Change record status: 
Published (View all published change records)
Project: 
Drupal core
Introduced in branch: 
10.2.x
Introduced in version: 
10.2.0
Issue links: 
https://www.drupal.org/node/3348789
Description: 

The ajax_page_state query parameter holds information about previously loaded libraries, so that AJAX requests only add new libraries that are needed.

To allow AJAX GET requests to succeed without reaching hosting limits for URL length, the value of the libraries item is now compressed when in query parameters and Drupal.settings.

This should be transparent for all PHP code dealing with ajax_page_state, because the query parameter is uncompressed in Drupal's query object, meaning this should not affect contrib modules unless they are replacing parts of the AJAX system, or using the information about libraries on the client side.

Impacts: 
Module developers