The stub tennon is a short tennon that isn't pegged, in this case it's on the bottom of a post that carries ~1/8th the weight of the house. It's unlikely to pop out and once the sheathing goes on it'll be tied to the sill
This happy looking item is my tennon checker, the upper slot is 1-1/2" and the lower is 2".
It's happy because the tennon fits the 1-1/2" slot without slop or binding.
Also in good view is one of my saw horses made from lumber milled on the Logosol.