What MetaTrader Administrators actually own
The MT4 / MT5 admin owns the live trading environment. That includes symbol and group configuration, swap and commission setup, leverage tiers, manager-side execution rules, plugin installation and bridge configuration to liquidity providers.
On the MT5 side it also covers backend reporting, custom server-side scripts and integration with risk and CRM systems. Brokers running hybrid B-book / A-book models lean heavily on the MT admin to keep the routing logic clean and auditable.