NodeRT_Windows_Foundation_Diagnostics.node

Node.js native addon Reference

A .node file is a native addon for Node.js. The file is a shared library with compiled code, renamed to .node. The require function of Node.js loads the addon like a module. Packages use addons when JavaScript alone is too slow or when they call system libraries. The binary matches one platform and processor architecture.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.