This is NME, the Next-generation Machine Emulator, an extensible platform for creating & implementing dynamic machine specifications and running/testing/debugging them.
Originally conceived & developed by Matthew Fredette at MIT, as TME - The Machine Emulator - this is the continuation & expansion of that groundbreaking project, described here: https://people.csail.mit.edu/fredette/tme/
It is the successor to that project and has the blessing of the original developer. Much work has already been done to bring the project up to par with current standards for host configuration and platform compliance. Many new features have been added, including bug fixes, true multithreading, networking enhancements, updated graphics libraries, and portability improvements. In the last regard, it now supports all major platforms including the major Linux, BSD, Windows, MacOS, and Solaris distros running on any particular hardware.