Fernflower: the first analytical decompiler - what does that mean?

I'm not sure if this is the best place to ask this, but since as I understand it Fernflower is a part of InteliJ Idea.

The readme (https://github.com/JetBrains/intellij-community/tree/master/plugins/java-decompiler/engine) says:

Fernflower is the first actually working analytical decompiler for Java and probably for a high-level programming language in general.

I've tried looking up the term "analytical decompiler", but the only things you find are the readme and blogposts parroting pretty much the same sentence. What does that actually mean? What is an "analytical decompiler"?