Huh. I'm familiar with the Spring RTS FOSS project (https://springrts.com) which started as a reimplementation of TA, and of course Planetary Annihilation, but not "Beyond All Reason" - do you have an authoritative link?

BAR is a really great RTS game. By far the best one today. It is very balanced and has a lot of depth. Highly recommended for any RTS enthusiast.