What is the purpose of a "glitch resistor" in the B+ supply of a tube amp?

During a tube arc or other HV fault, it limits current and dissipates the HVPS energy, protecting the tube/power supply

It blows open during a fault, limiting current and acting as a HV fuse

It protects the amp and doubles as a shunt for measuring anode current

It's an optional component that usually causes more trouble than benefit

Answer: It limits current and dissipates the energy stored in the cap bank. A properly sized component shouldn't blow. The only component that should act as a fuse is a fuse!