What is this braided wire?
It is unusual for single conductor with cloth braid to be used except for feeder wiring like that. Cloth braid was common up to the 50’s  but normally there were 2 wires in the cable when run loose.  knob and tube also ran single insulated wires down walls but normally maintained separation of the conductors and was not allowed to wander like or to use the same hole through a wooden member .  so it may have been a diy job of old or a addition to the system,

many states did not have the strict rules we have today even though the national electric code was established pre 1900 it Was probably an addition. If both wires enter the metal box in the same hole that would be more evidence that it probably was a later modification.