I have been using MuseScore since the very beginning and we are now to version 4 which is crazy amazing beyond my wildest dreams for this platform and software. However, I am very disappointed that the Euphonium or Baritone Horn is not listed and has never had its own sound. Although developers would probably like us to use Trombone or Tuba, they simply do not sound the same or come even close.
Most times I use cello to imitate the range of the Euphonium, but it limits what I can actually write for the horn without having to play it myself. PLEASE give the Euphonium its own sound. Thank you!
See #324929: Euphonium does not have native sound/playback