NEMA 0183 $GNRMC on SparkFun GPS Breakout - NEO-M9N, SMA (Qwiic)

I have been using an older GPS breakout that output $GP. I just change to your SparkFun GPS Breakout - NEO-M9N, SMA (Qwiic). Everything works as far as receiving data. However, from the NEMA sentence below, I have an additional “V” just prior to the checksum. The “N” just prior is the NEMA 2.3 mode, but I cannot find anything on the “V”. Any help would be appreciated. It does not occur on the other NEMA modes (GGA, VTG, etc.),

$GNRMC,161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,N,V*10

I’ve looked but unfortunately I can’t find any detailed technical information on that NEMA sentence.

If anyone else knows a good reference for the newer sentences, please share.