The original Espresso code comes from the 1989 Berkeley code (https://embedded.eecs.berkeley.edu/pubs/downloads/espresso/index.htm). See the COPYING file for original code license.

This is just a streamlined version of previous modernization efforts:

• C89 port by Andrew: https://github.com/Rupan/espresso/tree/master/jni/espresso
• C99 port and NodeJS bridge by Sébastien Cottinet: https://github.com/scottinet/espresso-logic-minimizer