You're right that the circled item is an adjuster, but it is not a "self" adjuster.
Self adjusters need an actuator assembly that puts some pressure on the adjuster like in the diagram below:
View attachment 384081
There is no such actuator in our parking brake system. We simply have the star wheel (adjusting assembly).
Okay then! I could swear I heard them click to adjust when engaging the PB in reverse periodically. So that is strictly for manual adjustment then. This is good to know. Thank you for correcting me.
Here is another good vid for those who would need it: