Ah! Give me a couple hours--I'm building an LST today and will show how these fit in. They were little goodies that I had made for personal projects that I found helpful enough that I thought I'd include them with tools for customers.
The yellow pieces can be swapped out with the clamps on the side of the tool to be used to balance the tool when it is set on a long, thin piece of material. I was engraving some signs on a 2x6 and found that when the tool jogged in the X direction it would wobble on the board. The height is meant to be adjusted until the yellow piece rests on the ground, supporting the tool against tipping.
The little blue pieces slide into the rectangular cutouts in the front and back of the tool to act as a fence. Again--these were made for a sign cutting project I was working on where I wanted to ensure that the boards were perfectly aligned with the Y axis along the length of the tool. I just snap one into each end in the slot corresponding to X=0 and I know that my board is lined up.
I'll get some photos today and post them here.