In the endurance rides of the 4 week FTP booster workout (once every week and twice during the last week) it says in the description you should stay in zone 2 for the one hour ride. However in the graph of the zone distribution it shows a 100% zone 3. So, I guess there’s an error, either in the graph or in the description. Should you ride for one hour in zone 2 (better recovery) or zone 3 (pushing yourself a little bit more but therefore less of a recovery ride)?
Yes, it is a free ride. So technically, anything goes. But I guess the original author of the workout had something in mind by saying “aiming to keep power in zone 2” or displaying 100% zone 3.
But okay, I just had a look at the week 4 day 3, which has a 10 minutes best effort free ride (So probably a zone 4 average), and 4 minutes of zone 3 quite at the beginning of the workout, but a total of 25% percent zone 2 (i.e. 14 minutes).
Conclusion: I guess free rides are always shown in the green zone 3. However the workout description is important. If it says “go as hard as you can”, then do that.
If it says “aiming to keep power in zone 2” (like in the endurance workouts) then zone 2 is relevant! So the endurance workouts are meant be kind of relaxed recovery rides.