K0879S1190 is 879km/hr at 11900 metres altitude.
roughly 474knots at FL390.
Airspeed in True Airspeed.
Knots is marked N (Nautical Mile derivative)
I know the CIS states (ie Russia and similar) used to use the Metric Metres for Altitude, but changed this a few years back so that Metric is only used under the transition altitude, and Feet/FL above transition.
About the only place that still uses Metres for altitudes is China/Mongolia as far as I am aware?
If you were flying the same profile in (places that are not China/Mongolia) it would be N0474F390
The Km/Hr and Foot Flight Level sounds like what would happen over Russian/Former CIS areas now that their Flight Levels are in feet. (I assume their Km/Hr is still Km/Hr).