For what it’s worth, the recent UA podcast on the Cham Mountain Fit program teed it up as a “transition strength” routine. Based on my understanding of the book and from that discussion, it’s basically something to do in the early stages of structured training. I believe that in TFNA they state that if you’re regularly in the gym doing a diverse array of strength work, you can keep the transition period to a few weeks before moving on to a max strength phase.
For me, I’d been out of the gym for about two years so did a longer (8+ weeks) transition strength phase, using the routines in TFNA. It looks like the 5 week alpine rock program includes a general strength day each week, for which you could substitute a CMF workout.