what does this mean: "running xacts with xcnt == 0"

Could someone translate this detail message to English:
       ereport(LOG,               (errmsg("logical decoding found consistent point at %X/%X",
(uint32)(lsn >> 32), (uint32) lsn),                errdetail("running xacts with xcnt == 0")));
 

(or downgrade to debug message, if appropriate)?