In addition, a new section about Modular Plugins is available in the IntelliJ SDK Docs.
In v2, a plugin is now split into explicit content modules — each with its own descriptor, dependencies, and classloader.
It leads to explicit module isolation, better plugin reload, improved dependency handling, and is a prerequisite for Remote Development support.
Will module com.intellij.modules.lang be available for Remote Development(JetBrains Gateway/JetBrains Client/Code With Me Guest/etc)? because my plugin Rainbow Brackets depends on it.
These plugins and similar are going to be dropped soon, as we completely merge them with a corresponding language plugin. They were used in the past as an intermediate solution only.