But yes, the previous poster's shrieks of alarm are unwarranted. Properly
done K&T wiring in good condition (as the wiring in this particular house
is) is no less safe than modren wiring methods.

Heck, if anything, it is safer.

It takes a lot of care to initially install K&T wiring as compared to just
slapping down some romex and putting in a few staples. K&T doesn't depend
upon the insulation of the individual conductors to prevent a short. The
knobs and tubes are made of a ceramic.

K&T wiring doesn't have a separate ground conductor and until GFCIs became
available, that increased the risk of shock from appliances and in wet
areas.

Powering a section of K&T from a GRCI breaker creates a very safe situation.