flag is a tag to represent the connectivity of a contig in the
assembly graph. flag=1 means the contig is standalone, flag=2 a looped
path and flag=0 for other contigs.
multi is roughly the average kmer coverage. But the figure is not
precise and if you want to quantify the coverage of a contig, I would
suggest you align the reads back to the contigs by short read
aligners.
Ah, ok thank you.