Thanks all who have commented. Yes,the 100 amp is for the windlass and I'll assume the 125 is the main breaker panel. I tested the 60 amp on the hydronic cabin heater and the bilge pump, neither of which seem to be fused, and came up empty. Also I tested against the navigation equipment, including the auto-pilot and everything worked fine while it was tripped.
So it's a mystery that will require an actual line trace, though it had a #2 sticker on it??
Meanwhile, I'll replace the hard fuse on the windlass as the new Lewmar V1came with a dedicated breaker and I suppose that will yield a spare100 amp fuse for the distribution panel.
Thanks again for the suggestions and guidance. I'm a better boat owner because of all of you.