This specific 3D model, "Excavator 3D model 6", is an asset made available by "Unknown author".
Can be downloaded at "Unknown platform" by following the link.
The license for this digital asset is "Unknown license".
STL (Stereolithography, filesize: 962 KB), OBJ (OBJ, filesize: 882 KB), FBX (Autodesk FBX, filesize: 1.55 MB)