TRANSFORMER WIRE COLORS

Transformer and Wire Color Standards for Tube amps
From Orr's Radio Handbook: And on old transformers, the colors may have faded to the point brown looks black or green looks black or brown, and so forth. I'm not aware of any standard for filament winding numbering, so if there is more than one, verify the voltages.
Transformer Lead Color Code - RF Cafe
Transformer Lead Color Code: A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors — the transformer's coils or "windings". Except for air-core transformers, the conductors are commonly wound around a single iron-rich core, or around separate but magnetically-coupled