MachXO5 devices base package is based on caBGA and BBG is the variation.
Per stated in Part Number Description, Lattice support both BBG256/400 packages.
User should follow BBG package Thermal Resistance Specification for MachXO5 devices.
Example:
LFMXO5-25-7-BBG256I is stated as caBGA Lead free package, but the part number imply that it is BBG256.