The first part addresses the OP’s confusion about the booster, but the second part confuses me.  How does brake fluid get drawn into the intake system?

From: Jim Arnott
Sent: Friday, October 15, 2021 2:43 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 82 air cooled automatic vanagon

The booster is forward of the instrument cluster (Bentley 47.10)  not in the engine compartment.

Blown power brake booster and master cylinder..  The white smoke was the brake fluid being drawn into the intake system and burning. No start may be a combination of vacuum leak (to the brake booster) and/or fouled plugs from the brake fluid.