Plugin

If you have an error like this, when you use a custom views filter plugin, the resent is now you need to have a config schema for all Views filter plugins.

The error :

Drupal 8 embedded with a plugin system. In drupal 8, Plugin is a group of PHP classes used for a defined specific usage. You can use any registered  plugins, add new plugins and also create your own plugin type.

Create a new Plugin Type in Drupal 8

Example from Drupal 8 example module, Thank you.
See the Drupal 8 'Example' contrib module for full details and source

Module name : 'plugin_type_example'

 

Plugins are small pieces of functionality that are swappable. Plugins that perform similar functionality are of the same plugin type.

Link : https://www.drupal.org/developing/api/8/plugins

In drupal 8 block is part of the plugin system.

Step 1. Create a simple module like this.