what is stl part in devfoam program?

In DevFoam, the STL part refers to a file format that’s used for 3D modeling. STL stands for “stereolithography,” and it’s commonly used for 3D printing and computer-aided design (CAD). It basically contains information about the surfaces of a 3D object and is often used to create 3D models in various software applications.

You can import the stl. file into CNC foam cutting machine,it needs Devfoam to draw and generate cutting path,another program is mach3,it is to control the machine.