Switched on from GUI script command 'PFb0cON' (for block 0), which runs command mkARpfilt.
int LINARFILTERPRED_Build_LinPredictor(const char *IDin_name, long PForder, float PFlag, double SVDeps, double RegLambda, const char *IDoutPF, int outMode, int LOOPmode, float LOOPgain)