Change record status: 
Project: 
Introduced in branch: 
9.4.x
Introduced in version: 
9.4.0-alpha1
Description: 

The admin/appearance page now includes a warning about themes that have either deprecated or obsolete as the value of lifecycle in their .info.yml file. For example, the warning on a deprecated theme looks something like this (depending on the styles of your administration theme):

Screenshot of the admin/appearance page showing a deprecated theme

Impacts: 
Site builders, administrators, editors
Themers
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done