For zero config install of VE + Parsoid in MediaWiki 1.35 LTS release, we hacked it by copying the REST API and Config code (everything in extension/* in Parsoid) into the VisualEditor extension directory under a different namespace. Since that was meant to be a temporary hack, we have also since removed it from VE master.
So, for 1.36 release, if we don't manage to get Parsoid callable from core via library calls (instead of the REST API as required now), we will have to put that hack back into 1.36 release as well.
This task tracks the requirement of getting one of those two solutions working for 1.36.
(The task for the 1.35 LTS release was T248343: Uncached VisualEditor w/ Parsoid/PHP (no JS, no RESTBase) for MW 1.35 LTS, and the workaround to VE was added in 4b04f413fac75e37fbf31029e30fdd0888cb4336 and removed in 49a33873232163fc79b102d7e599e07c453fe2e9.)