(2) describing a split client+server architecture that may have just 1 server. This usage of "distributed architecture" in discussions was more common in 1980s/1990s with the rise of client/server computing. Visual Basic CRUD, PowerBuilder, SAP R/3, etc.
To answer your previous question: >I'm guessing they mean the architecture is decoupled, [...] but with a fancier word?
It's not a fancier word. Jetbrains is re-using an existing description of "distributed==client/server" that's been around for decades. It's just that "distributed computing" has been recently dominated by the examples of meaning (1) above.