This object specifies the DHCP Local Relay enabled VLAN in a string of octets containing one bit per VLAN for VLANs 2049 to 4094. If the bit is set to '1', then the VLAN is enabled for DHCP Local Relay.
Sources for this description
D-Link official switch MIBsD-Link MIB copies (LibreNMS/Observium Community)