Markup support so developers can register different markup engines and the UI can reflect it

Markup support so developers can register different markup engines and the UI can reflect it.

This just gives developers the ability to register markup engines in the editor service as a nickname. The developer must then listen to the on content renderers to build their markup engines. With this, the content object now has a markup field which you can use in the renderes to determine if you need to translate or not.