elasticsearch/docs/extend/index.md

mapped_pages
https://www.elastic.co/guide/en/elasticsearch/plugins/current/plugin-authors.html

Create Elasticsearch plugins [plugin-authors]

{{es}} plugins are modular bits of code that add functionality to {{es}}. Plugins are written in Java and implement Java interfaces that are defined in the source code. Plugins are composed of JAR files and metadata files, compressed in a single zip file.

There are two ways to create a plugin:

Creating text analysis plugins with the stable plugin API

Text analysis plugins can be developed against the stable plugin API to provide {{es}} with custom Lucene analyzers, token filters, character filters, and tokenizers.

Creating classic plugins

Other plugins can be developed against the classic plugin API to provide custom authentication, authorization, or scoring mechanisms, and more.