Specify how an output group's files will be represented in TargetComplete/AspectComplete BEP events. Values are an assignment of an output group name to one of 'NAMED_SET_OF_FILES_ONLY', 'INLINE_ONLY', or 'BOTH'. The default value is 'NAMED_SET_OF_FILES_ONLY'. If an output group is repeated, the final value to appear is used. The default value sets the mode for coverage artifacts to BOTH: -- experimental_build_event_output_group_mode=baseline.lcov=both