There are three extension types.
- Plain Extensions
- Node Extensions
- Mark Extensions
The node and mark extensions get their name from the underlying prosemirror implementation. If you have time it's not a bad idea to peruse though the prosemirror documentation. The ending will really surprise you.
Naming conventions for npm packages
- remirror-preset-<%NAME> For composing extensions.
- remirror-extension-<%NAME> For adding behaviour.
- remirror-editor-<%NAME> For adding UI to the editor.