There is only one file type that uses the .THING extension:
MakerBot Thing File
3D model file used by MakerBot Desktop, an application that allows users to send 3D models to 3D printers; stores multiple .STL files arranged to be printed together; includes an XML manifest.
The THING file format is used as a container for STL files for 3D printing. It is compressed with Zip compression and allows you to continue to edit the the different components of a plate in MakerBot Desktop separately.
Updated: July 15, 2016