COMMON_REF         91 fetch-pack.c   				   COMMON | COMMON_REF | SEEN | POPPED);
COMMON_REF        156 fetch-pack.c   		} else if (commit->object.flags & COMMON_REF)
COMMON_REF        640 fetch-pack.c   			rev_list_push((struct commit *)o, COMMON_REF | SEEN);