With more data, it seems that the spark in this case started in the retractable awning system while the tenant was on a travel. I assume that the awning tried to retract on strong wind circumstances and maybe got stuck on a loop? Or maybe the wind damaged physically the system and tore off the cables creating a short-circuit.

The flammable cladding did the rest.

That lead me to ruminate about if "your smart home can kill you" has finally happened.