Nomenclature of FALCON contigs

[dcopetti]

Hi, I am analyzing the p- and a-contigs of a FALCON assembly, and within the p-contigs I see that there are canonical linear contigs (e.g. 003655F), circular contigs (3702) and linear "R" contigs (002733R). What are the latter ones? Are there other codes we should expect? Assembling plant genomes (>200 Mb, linear chromosomes) is there a reason to keep circular or R contigs 10-50 kb long? (unless they may be organelles of course) Thanks