Large table tops benefit from breadboard ends. They help keep the assembly flat and protect end-grain.
I lay out the tenon and stub tenon and use a plunge router with a straight bit to form the tenons, I saw out the waste using a jigs saw and a handsaw.
The breadboards are dadoed to receive the stub tenon and slot mortised to receive the tenons.
Once they are fitted I clamp them in place and drill through the whole assembly to locate the pegs.
The slots in the outer tenons are later widened to allow for movement.
Here we are right before assembly.