Roll Over Valve
WARNING: This page is about a different car, the 2018 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.
The three roll over valves allow fuel vapor to escape to prevent tank pressurization in normal vehicle operating modes. The valves are designed to close to prevent fuel leakage through the vents in the event of a vehicle roll over. The fuel vapor is routed to the Evaporative Emission (EVAP) canister where it is stored before being purged at intervals to the engines intake manifold.