Galician is fully translated and ready to be available in xfce.org.
Pasi Lallinaho referenced this bugreport in commit dea1dd3584f641099c92710a430787b1552e8962 Add Galician (gl) to the list of supported languages. (Bug #15118) https://git.xfce.org/www/www.xfce.org/commit?id=dea1dd3584f641099c92710a430787b1552e8962
Committed to Git, production should get with this change today.