A couple of fellow enthusiasts ported the BREXX language to MVS3.8j TK4- ! A Herculean task indeed… Here’s a quote from their announcement:
After good progress in the last months, we are just about ready to ship the first MVS release of BREXX/370. Thanks to all who have helped in testing the previous alpha version. We entered the code freeze zone and will perform testing and plan to ship the new software by May 1, 2019.
This document will cover important changes and improvements on a high level. Details of the described functions and commands will be documented in detail in the BREXX/370 User’s Guide, which will be delivered with the software launch.