Looks like a split nut driver. I only ever see those on old handsaws. They are used when a flush nut is required. They are slotted, but the center of the slot is usually filled by the bolt’s tail. Thus the tool with two pins basically, to straddle the tail of the bolt.
They probably have been used by other industries. Pretty sure Snap on wouldn’t make a tool for old hand saws. But that looks like what that’s for.
Oh guns sometimes had these. Gun guys use special screwdrivers for them. But a 1/4” socket makes sense.
There are standardized slotted nuts, at least in Europe, and probably in the USA, although maybe not ultra common.
PB Swiss makes ten sizes of drivers for different sized slotted nuts, and I’m fairly certain the sizing system likely goes larger.
I’ve seen the nuts on power tools, sewing machines, and the fold out wheelchair ramps on Busses.
They’re also found on firearms.
The main difference between the “standard” slotted nuts, and saw nuts, is that saw nuts tend yo have a very thin slot in comparison to the nut size, where the European standard has a wider slot.
