Is SceneTree order of node instantiation and readying dependable?

[system]

	Attention	Topic was automatically imported from the old Question2Answer platform.
	Asked By	goshot

If R is Viewport root and N is root node, can I always assume A1 _ready will run before B _ready so that get_node("root/N/A/A1") in B _ready will resolve to a fully instanced, scene-tree added, and ready A1?

    R
    |N
     |A
      |A1
     |B

This documentation suggests yes and testing so far supports, but I want to confirm this top-to-bottom order includes full depth first traversal and is strongly intended as Godot philosophy rather than current state of implementation:

Using SceneTree