Change record status: 
Project: 
Introduced in branch: 
2.0.x
Introduced in version: 
2.0.0
Description: 

Group relation types can provide operations for the UI where all of the plugins are managed for a group type. This functionality has been moved to "operation_provider" handlers so that they are more easily altered from the outside.

Have a look at src/Plugin/Group/RelationHandlerDefault/OperationProvider.php for an example.

Impacts: 
Module developers
Site templates, recipes and distribution developers