jpegexiforient is a tool that allows querying and setting of the orientation field in JPEG EXIF data. It comes from JPEGclub.org, details of how and why you use it are available there and the original source code (which should match what is checked in here) can also be downloaded from there.
The reason for making a copy here is that, while it is often included with the jpegtran package in Linux distributions, I was not easily able to find a Windows executable and I want to use this executable in a cross-platofrm application (https://github.com/CiderMan/PGTips). This project is solely intended to provide Windows "releases" of jpegexiforient.