Understanding the "doveadm replicator status" output

Where can I get more detailed information about the output of the 'doveadm replicator status' ? man doveadm-replicator isn't enough.

For example, Total number of known users = 29409, but the server has only 17667 users. This is confusing. Look: # doveadm user '*' |wc -l 17667

# doveadm replicator status Queued 'sync' requests 0 Queued 'high' requests 0 Queued 'low' requests 0 Queued 'failed' requests 0 Queued 'full resync' requests 12962 Waiting 'failed' requests 16447 Total number of known users 29409

What it means to "Queued full resync requests" ?

thanks! Thiago Henrique