There is only one file type that uses the .MAKERBOT extension:
MakerBot Print File
3D printer file format used by MakerBot Replicator, a desktop 3D printer; contains 3D model printing instructions for a MakerBot desktop 3D printer.
The MAKERBOT format is designed to deliver instructions from a 3D model file, such as .STL or .OBJ, to the MakerBot Replicator in order to print the 3D object. If MakerBot Desktop is connected to MakerBot Replicator, you can create the MAKERBOT file with MakerBot Desktop by clicking "Print" to slice the model and send the MAKERBOT file to the MakerBot Replicator. If MakerBot Desktop is not connected to MakerBot Replicator you can save the MAKERBOT file and transfer it via USB drive.
Updated: June 24, 2016