Problem/Motivation
Symfony dump() function can be used in Drupal tests (and in Drupal in general!) for debugging output.
However, if you dump() a whole entity or a plugin, you get a HUGE amount of output on the terminal, because an entity object includes the field definitions, which in turn have the definitions of ALL the field types and the data types. Similarly, plugins can have a large amount of data from injected services.
Steps to reproduce
Load an entity in a kernel test and dump() it.
Proposed resolution
Symfony's VarDumper component provides various ways in which the output can be customized: https://symfony.com/doc/current/components/var_dumper/advanced.html
For example, one quick and dirty way would be to register a caster for the entity and plugin base classes and unset some of the internal properties -- like this code does: https://github.com/joachim-n/mutable-typed-data/blob/main/Test/src/VarDu...
More elegantly perhaps, a Cloner can be registered and use withRefHandles() to remove the properties.