"these were among the most liquid currencies across emerging markets. The name for the new reserve currency — R5 or R5+ — was based on the first letters of the BRICS currencies all of which begin with the letter R (real, ruble, rupee, renminbi, rand)”: https://thecradle.co/article-view/20532/global-south-gold-backed-currencies-to-replace-the-us-dollar