Facebook moved from subversion to git around 2008. Some of their teams then switched to mercurial around 2014 (I could be wrong by a couple years here or there)

Facebook moved from subversion to git around 2008. Some of their teams then switched to mercurial around 2014 (I could be wrong by a couple years here or there). By 2014, git was already the main tool everyone was using —- no amount of backing by a single company would have tilted the scales.