It was in a variac, connecting the wiper to its terminal. It had a
connector tab on each end & was inside the sleeve. It's lead colored,
but much stiffer than lead - zinc?. The variac is 20A resistive, 14A
otherwise. It failed with a pop when an end connector came off.

I dunno what else it might be, but it was really inaccessible,
underneath the terminal block - a terrible location for a fuse. And
where would you get a replacement?

https://i.imgur.com/y0RREz0.jpg