Do we have a new rule to always introduce type specific prefixes? I have also seen this in RJ's latest code. But I am not a fan of it, because it is hard to maintain rules for it (except of the very handy leading "p" for pointers) and modern IDEs are showing the type anyway. In this case I would prefer m_group to match other places in Mixxx. "s" is misleading because it can be a QString as well.