What "context" are you referring to? The section title is "FLAME". The sentence mentions both falling burning rubble and wreck blazes. The section itself deals with all aspects of flame counters, including that a newly placed one can't spread (is marked with a PIN counter) and that > one can exist in a Location. It would seem a very daring interpretation indeed that B25.15 is meant to apply to falling burning rubble only, if that is what you are saying.
B25.15 "All Fires start as Flames, except for Wreck Blazes and those spread by falling burning rubble."
What I mean is that it is about fires - all start as flames normally.
a) Wreck Blazes (the fire of a burning wreck is ablaze immediately, there is no flaming wreck (no pun intended) before that i.e. there is no spreading
a wreck flame into a wreck blaze).
b) Fire spread by falling burning rubble (If you have a blazing building collapse and spreading
in this way i.e. dropping the whole burning havoc onto an adjacent street, then that fallen rubble is already ablaze and not aflame.
In other words:
Fire ALWAYS spreads via a flame, except no spread
"within" a wreck as it blazes from the start, and no flame but a blaze from the start if it spreads
as falling rubble from an ablaze collapsing building. So no "spreading" context within a wreck but only with falling burning rubble.
With a vehicle in bypass of burnable terrain this would mean:
At first no flaming tank but immediately blazing tank then flaming burnable terrain then blazing burnable terrain as the order of the fire expanding.