Staffing vault — backs the network's running and staffing from its family share, not discretionary spend.
MSV is the vault that backs the network's running and staffing. It is funded by its family share — the pro-rata LEG 2 it receives as a member of the V3 splitter — rather than by anyone's discretionary spend.
Like CBI, MSV is also run as a burn-boost family under the Overhead cause: its engine retires MSV units into the registry sink on the daily cycle.
MSV is both a vault that funds the upkeep and an engine whose impact is retired forever.