Robert Vervoordt wrote:

I heard this about Kodachrome, but read it in manuals describing the
machine processing of Eastman Color Negtive motion picture film.
Several long time laboratory men confirmed this about both processes.

RemJet removal precedes development.

There's a document on Kodak's web site that describes the Kodachrome
processing steps. The very first step is the removal of the Remjet
backing. The description is as follows:

Backing Removal Solution - The alkaline backing removal solution
converts the rem-jet antihalation backing on the film base into a
water-soluble form. This backing is removed in the backing removal
wash.

Backing Removal Wash - This wash performs two functions:
1. It removes the backing removal solution from the film.
2. It completely removes the solubilized antihalation backing
from the base by a combination of water action and mechanical
buffing.

The next step is the first developer.