I have seen several examples but this one captures my question perfectly
That is the bench from this question. As you can see there is a nice arrangement of holes along the skirt. As well as a couple of holes on the right-hand side leg. The latter I mostly know the answer for as I keep seeing holdfast put in there.
What about the ones on the skirt? I'm sure they are more than just decoration. I am aware that the holes in the tops are bench dog holes for using with holdfasts, bench dogs and stops. Just never seen them on the side.